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Linux CVE-2025-22115

MEDIUM
Race Condition (CWE-362)
2025-04-16 416baaa9-dc9f-4396-8d5f-8c081fb06d67
4.7
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V15 - Secure Coding and Architecture Concurrency control, locking
MITRE ATT&CK

1 technique across 1 tactic: Privilege Escalation

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS score of 4.7 (MEDIUM). Attack characteristics: local attack vector, high complexity, low privileges required, no user interaction not required. EPSS exploitation probability: 0.05%.

Exploit ScenarioDerived

Successful exploitation could compromise the medium-severity affected system.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 28, 2026

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix block group refcount race in btrfs_create_pending_block_groups() Block group creation is done in two phases, which. Rated medium severity (CVSS 4.7).

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified under CWE-362. In the Linux kernel, the following vulnerability has been resolved: btrfs: fix block group refcount race in btrfs_create_pending_block_groups() Block group creation is done in two phases, which results in a slightly unintuitive property: a block group can be allocated/deallocated from after btrfs_make_block_group() adds it to the space_info with btrfs_add_bg_to_space_info(), but before creation is completely completed in btrfs_create_pending_block_groups(). As a result, it is possible for a block group to go unused and have 'btrfs_mark_bg_unused' called on it concurrently with 'btrfs_create_pending_block_groups'. This causes a number of issues, which were fixed with the block group flag 'BLOCK_GROUP_FLAG_NEW'. However, this fix is not quite complete. Since it does not use the unused_bg_lock, it is possible for the following race to occur: btrfs_create_pending_block_groups btrfs_mark_bg_unused if list_empty // false list_del_init clear_bit else if (test_bit) // true list_move_tail And we get into the exact same broken ref count and invalid new_bgs state for transaction cleanup that BLOCK_GROUP_FLAG_NEW was designed to prevent. The broken refcount aspect will result in a warning like: [1272.943527] refcount_t: underflow; use-after-free. [1272.943967] WARNING: CPU: 1 PID: 61 at lib/refcount.c:28 refcount_warn_saturate+0xba/0x110 [1272.944731] Modules linked in: btrfs virtio_net xor zstd_compress raid6_pq null_blk [last unloaded: btrfs] [1272.945550] CPU: 1 UID: 0 PID: 61 Comm: kworker/u32:1 Kdump: loaded Tainted: G W 6.14.0-rc5+ #108 [1272.946368] Tainted: [W]=WARN [1272.946585] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014 [1272.947273] Workqueue: btrfs_discard btrfs_discard_workfn [btrfs] [1272.947788] RIP: 0010:refcount_warn_saturate+0xba/0x110 [1272.949532] RSP: 0018:ffffbf1200247df0 EFLAGS: 00010282 [1272.949901] RAX: 0000000000000000 RBX: ffffa14b00e3f800 RCX: 0000000000000000 [1272.950437] RDX: 0000000000000000 RSI: ffffbf1200247c78 RDI: 00000000ffffdfff [1272.950986] RBP: ffffa14b00dc2860 R08: 00000000ffffdfff R09: ffffffff90526268 [1272.951512] R10: ffffffff904762c0 R11: 0000000063666572 R12: ffffa14b00dc28c0 [1272.952024] R13: 0000000000000000 R14: ffffa14b00dc2868 R15: 000001285dcd12c0 [1272.952850] FS: 0000000000000000(0000) GS:ffffa14d33c40000(0000) knlGS:0000000000000000 [1272.953458] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [1272.953931] CR2: 00007f838cbda000 CR3: 000000010104e000 CR4: 00000000000006f0 [1272.954474] Call Trace: [1272.954655] <TASK> [1272.954812] ? refcount_warn_saturate+0xba/0x110 [1272.955173] ? __warn.cold+0x93/0xd7 [1272.955487] ? refcount_warn_saturate+0xba/0x110 [1272.955816] ? report_bug+0xe7/0x120 [1272.956103] ? handle_bug+0x53/0x90 [1272.956424] ? exc_invalid_op+0x13/0x60 [1272.956700] ? asm_exc_invalid_op+0x16/0x20 [1272.957011] ? refcount_warn_saturate+0xba/0x110 [1272.957399] btrfs_discard_cancel_work.cold+0x26/0x2b [btrfs] [1272.957853] btrfs_put_block_group.cold+0x5d/0x8e [btrfs] [1272.958289] btrfs_discard_workfn+0x194/0x380 [btrfs] [1272.958729] process_one_work+0x130/0x290 [1272.959026] worker_thread+0x2ea/0x420 [1272.959335] ? __pfx_worker_thread+0x10/0x10 [1272.959644] kthread+0xd7/0x1c0 [1272.959872] ? __pfx_kthread+0x10/0x10 [1272.960172] ret_from_fork+0x30/0x50 [1272.960474] ? __pfx_kthread+0x10/0x10 [1272.960745] ret_from_fork_asm+0x1a/0x30 [1272.961035] </TASK> [1272.961238] ---[ end trace 0000000000000000 ]--- Though we have seen them in the async discard workfn as well. It is most likely to happen after a relocation finishes which cancels discard, tears down the block group, etc. Fix this fully by taking the lock arou ---truncated--- Affected products include: Linux Linux Kernel.

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Severity by source

NVD PRIMARY 4.7 MEDIUM
AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
SUSE MEDIUM

Primary rating from NVD.

CVSS VectorNVD

Attack Vector
Local
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Lifecycle Timeline

2
Patch released
Mar 28, 2026 - 18:37 nvd
Patch available
CVE Published
Apr 16, 2025 - 15:16 nvd
MEDIUM 4.7

DescriptionNVD

In the Linux kernel, the following vulnerability has been resolved:

btrfs: fix block group refcount race in btrfs_create_pending_block_groups()

Block group creation is done in two phases, which results in a slightly unintuitive property: a block group can be allocated/deallocated from after btrfs_make_block_group() adds it to the space_info with btrfs_add_bg_to_space_info(), but before creation is completely completed in btrfs_create_pending_block_groups(). As a result, it is possible for a block group to go unused and have 'btrfs_mark_bg_unused' called on it concurrently with 'btrfs_create_pending_block_groups'. This causes a number of issues, which were fixed with the block group flag 'BLOCK_GROUP_FLAG_NEW'.

However, this fix is not quite complete. Since it does not use the unused_bg_lock, it is possible for the following race to occur:

btrfs_create_pending_block_groups btrfs_mark_bg_unused if list_empty // false list_del_init clear_bit else if (test_bit) // true list_move_tail

And we get into the exact same broken ref count and invalid new_bgs state for transaction cleanup that BLOCK_GROUP_FLAG_NEW was designed to prevent.

The broken refcount aspect will result in a warning like:

[1272.943527] refcount_t: underflow; use-after-free. [1272.943967] WARNING: CPU: 1 PID: 61 at lib/refcount.c:28 refcount_warn_saturate+0xba/0x110 [1272.944731] Modules linked in: btrfs virtio_net xor zstd_compress raid6_pq null_blk [last unloaded: btrfs] [1272.945550] CPU: 1 UID: 0 PID: 61 Comm: kworker/u32:1 Kdump: loaded Tainted: G W 6.14.0-rc5+ #108 [1272.946368] Tainted: [W]=WARN [1272.946585] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014 [1272.947273] Workqueue: btrfs_discard btrfs_discard_workfn [btrfs] [1272.947788] RIP: 0010:refcount_warn_saturate+0xba/0x110 [1272.949532] RSP: 0018:ffffbf1200247df0 EFLAGS: 00010282 [1272.949901] RAX: 0000000000000000 RBX: ffffa14b00e3f800 RCX: 0000000000000000 [1272.950437] RDX: 0000000000000000 RSI: ffffbf1200247c78 RDI: 00000000ffffdfff [1272.950986] RBP: ffffa14b00dc2860 R08: 00000000ffffdfff R09: ffffffff90526268 [1272.951512] R10: ffffffff904762c0 R11: 0000000063666572 R12: ffffa14b00dc28c0 [1272.952024] R13: 0000000000000000 R14: ffffa14b00dc2868 R15: 000001285dcd12c0 [1272.952850] FS: 0000000000000000(0000) GS:ffffa14d33c40000(0000) knlGS:0000000000000000 [1272.953458] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [1272.953931] CR2: 00007f838cbda000 CR3: 000000010104e000 CR4: 00000000000006f0 [1272.954474] Call Trace: [1272.954655] <TASK> [1272.954812] ? refcount_warn_saturate+0xba/0x110 [1272.955173] ? __warn.cold+0x93/0xd7 [1272.955487] ? refcount_warn_saturate+0xba/0x110 [1272.955816] ? report_bug+0xe7/0x120 [1272.956103] ? handle_bug+0x53/0x90 [1272.956424] ? exc_invalid_op+0x13/0x60 [1272.956700] ? asm_exc_invalid_op+0x16/0x20 [1272.957011] ? refcount_warn_saturate+0xba/0x110 [1272.957399] btrfs_discard_cancel_work.cold+0x26/0x2b [btrfs] [1272.957853] btrfs_put_block_group.cold+0x5d/0x8e [btrfs] [1272.958289] btrfs_discard_workfn+0x194/0x380 [btrfs] [1272.958729] process_one_work+0x130/0x290 [1272.959026] worker_thread+0x2ea/0x420 [1272.959335] ? __pfx_worker_thread+0x10/0x10 [1272.959644] kthread+0xd7/0x1c0 [1272.959872] ? __pfx_kthread+0x10/0x10 [1272.960172] ret_from_fork+0x30/0x50 [1272.960474] ? __pfx_kthread+0x10/0x10 [1272.960745] ret_from_fork_asm+0x1a/0x30 [1272.961035] </TASK> [1272.961238] ---[ end trace 0000000000000000 ]---

Though we have seen them in the async discard workfn as well. It is most likely to happen after a relocation finishes which cancels discard, tears down the block group, etc.

Fix this fully by taking the lock arou ---truncated---

Executive ViewAI

Why It Matters

CVE-2025-22115 presents moderate security risk, a race condition vulnerability rated CVSS 4.7. Exploitation could compromise the security of affected deployments. A patch is available and should be applied during regular vulnerability management.

Business Impact: Low
Compensating Controls

Apply vendor patch. If patching is delayed: implement rate limiting and resource quotas.

Threat Intelligence Overview

EPSS Score
0.0%
Top 85% exploitable
Data Quality
5 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.0%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Defer
Exploitation· derived
None
System Exposure· derived
Small
Automatable· derived
No
Human Impact
Low

Priority Score

24
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +24
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

Race conditions occur when multiple concurrent requests exploit the brief time gap between checking a condition and acting upon it (TOCTOU - Time of Check, Time of Use).

Affected Products (CPE)NVD

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.5:-:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.5:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.5:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.5:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.5:rc6:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.5:rc7:*:*:*:*:*:*

Vendor StatusVendor

SUSE

Severity: Medium
Product Status
Container suse/sl-micro/6.0/base-os-container:2.1.3-7.4 Container suse/sl-micro/6.1/base-os-container:2.2.0-4.37 Image SL-Micro Image SL-Micro-Azure Image SL-Micro-BYOS-Azure Image SL-Micro-BYOS-EC2 Image SL-Micro-BYOS-GCE Image SL-Micro-EC2 Image SLE-Micro Image SLE-Micro-Azure Image SLE-Micro-BYOS Image SLE-Micro-BYOS-Azure Image SLE-Micro-BYOS-EC2 Image SLE-Micro-BYOS-GCE Image SLE-Micro-EC2 Image SLE-Micro-GCE Image SUSE-Multi-Linux-Manager-Proxy-BYOS-Azure Image SUSE-Multi-Linux-Manager-Proxy-BYOS-EC2 Image SUSE-Multi-Linux-Manager-Proxy-BYOS-GCE Image SUSE-Multi-Linux-Manager-Server-Azure-llc Image SUSE-Multi-Linux-Manager-Server-Azure-ltd Image SUSE-Multi-Linux-Manager-Server-BYOS-Azure Image SUSE-Multi-Linux-Manager-Server-BYOS-EC2 Image SUSE-Multi-Linux-Manager-Server-BYOS-GCE Image SUSE-Multi-Linux-Manager-Server-EC2-llc Image SUSE-Multi-Linux-Manager-Server-EC2-ltd Affected
Container suse/sl-micro/6.0/kvm-os-container:2.1.3-6.27 Container suse/sl-micro/6.1/kvm-os-container:2.2.0-4.37 Affected
Container suse/sl-micro/6.0/rt-os-container:2.1.3-7.33 Container suse/sl-micro/6.1/rt-os-container:2.2.0-4.42 Affected
Image SLES15-SP6-BYOS Image SLES15-SP6-BYOS-Azure Image SLES15-SP6-BYOS-EC2 Image SLES15-SP6-BYOS-GCE Image SLES15-SP6-CHOST-BYOS Image SLES15-SP6-CHOST-BYOS-Aliyun Image SLES15-SP6-CHOST-BYOS-Azure Image SLES15-SP6-CHOST-BYOS-EC2 Image SLES15-SP6-CHOST-BYOS-GCE Image SLES15-SP6-CHOST-BYOS-GDC Image SLES15-SP6-CHOST-BYOS-SAP-CCloud Image SLES15-SP6-EC2 Image SLES15-SP6-EC2-ECS-HVM Image SLES15-SP6-GCE Image SLES15-SP6-HPC-BYOS Image SLES15-SP6-HPC-BYOS-Azure Image SLES15-SP6-HPC-BYOS-EC2 Image SLES15-SP6-HPC-BYOS-GCE Image SLES15-SP6-HPC-EC2 Image SLES15-SP6-HPC-GCE Image SLES15-SP6-Hardened-BYOS Image SLES15-SP6-Hardened-BYOS-Azure Image SLES15-SP6-Hardened-BYOS-EC2 Image SLES15-SP6-Hardened-BYOS-GCE Image SLES15-SP6-SAP Image SLES15-SP6-SAP-Azure Image SLES15-SP6-SAP-EC2 Image SLES15-SP6-SAP-GCE Image SLES15-SP6-SAPCAL Image SLES15-SP6-SAPCAL-Azure Image SLES15-SP6-SAPCAL-EC2 Image SLES15-SP6-SAPCAL-GCE Affected
Image SLES15-SP6-SAP-Azure-3P Image SLES15-SP6-SAP-Azure-LI-BYOS Image SLES15-SP6-SAP-Azure-LI-BYOS-Production Image SLES15-SP6-SAP-Azure-VLI-BYOS Image SLES15-SP6-SAP-Azure-VLI-BYOS-Production Image SLES15-SP6-SAP-BYOS Image SLES15-SP6-SAP-BYOS-Azure Image SLES15-SP6-SAP-BYOS-EC2 Image SLES15-SP6-SAP-BYOS-GCE Image SLES15-SP6-SAP-Hardened Image SLES15-SP6-SAP-Hardened-Azure Image SLES15-SP6-SAP-Hardened-BYOS Image SLES15-SP6-SAP-Hardened-BYOS-Azure Image SLES15-SP6-SAP-Hardened-BYOS-EC2 Image SLES15-SP6-SAP-Hardened-BYOS-GCE Image SLES15-SP6-SAP-Hardened-EC2 Image SLES15-SP6-SAP-Hardened-GCE Affected

References

Advisories & patches
PATCH https://git.kernel.org/stable/c/2d8e5168d48a91e7a802d3003e72afb4304bebfa PATCH https://git.kernel.org/stable/c/9d383a6fc59271aaaf07a33b23b2eac5b9268b7a PATCH https://git.kernel.org/stable/c/ee56da95f8962b86fec4ef93f866e64c8d025a58 ADVISORY https://ubuntu.com/security/notices/USN-8126-1 ADVISORY https://vuldb.com/vuln/305138 ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:01614/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:01707/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:01919/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:01964/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:01967/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:02385/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:02387/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:02388/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:02389/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:02390/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:02405/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:02411/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:02412/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:02413/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:02420/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:02421/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:02433/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:02439/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:02440/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:02442/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:02449/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:02514/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20343/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20344/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20354/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20355/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20517/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20518/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20519/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20520/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20521/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20524/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20525/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20526/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20527/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20528/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20529/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20540/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20541/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20542/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20543/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20544/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20545/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20546/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20547/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20548/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:20300/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:20327/ REF https://git.kernel.org/stable/c/3232bdf8a135877345c25bf4c0d892334a4c03f7 REF https://git.kernel.org/stable/c/77fd40b7ed0c3acf989a0f2a07b15a0a59ea8f96

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