Skip to main content

Linux Kernel CVE-2026-52910

| EUVDEUVD-2026-38034 HIGH
Signal Handler Race Condition (CWE-364)
2026-06-19 Linux GHSA-gj4p-2qjv-wchv
Buffer Overflow Linux Debian Ubuntu
7.8
CVSS 3.1 · Vendor: Linux
View

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Local user creates UDP SO_REUSEPORT group
  2. Delivery
    Attach cBPF steering filter via setsockopt
  3. Exploit
    Race: replace/detach filter while sending UDP
  4. Execution
    Reader dereferences freed cBPF prog (UAF)
  5. Persist
    Groom freed allocation for control
  6. Impact
    Kernel memory disclosure or privilege escalation

Vulnerability Assessment

Weakness
CWE
CWE-364
Exploitation Conditions

Exploitation requires local access to the target host and the ability to use SO_REUSEPORT UDP sockets with a classic-BPF (cBPF) reuseport filter attached via setsockopt (SO_ATTACH_REUSEPORT_CBPF / the reuseport_attach_prog/reuseport_detach_prog paths). The specific trigger is a race: the attacker must replace or detach the reuseport cBPF program from the setsockopt path at the same moment another thread is selecting a socket for an inbound UDP packet (reuseport_select_sock), so the freed program is read before RCU readers finish. Limiting factors that constrain real-world risk: it is local-only (CVSS AV:L - no remote/network trigger), it needs the reuseport+cBPF feature to be exercised (not a default for arbitrary processes, though any local user can opt into it), and reliable exploitation depends on winning a timing window and grooming the freed vmalloc/JIT allocation. eBPF reuseport programs are explicitly noted as not affected - the bug is specific to the cBPF free path.
Impact

The CVSS 3.1 vector (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H, base 7.8) describes a local, low-complexity, low-privilege attack with high impact across confidentiality, integrity and availability - consistent with a memory-corruption bug an unprivileged local user can reach via standard socket syscalls. This is corroborated by the description and KASAN trace, which show the bug is triggered from userspace by a UDP reuseport workload with no special capabilities. However, real-world exploitation signals are modest: EPSS is only 0.17% (6th percentile), the CVE is not in CISA KEV, and there is no published proof-of-concept beyond the reporter's syscall reproducer, which demonstrates a crash (KASAN OOB read) rather than weaponized code execution. Turning an RCU-timing UAF into reliable privilege escalation requires winning a race and grooming the freed allocation - non-trivial but not impossible for a skilled local attacker. Net assessment: a genuine local-EoP/DoS candidate worth patching in normal cycles, not an emergency drop-everything issue; remote exploitation is not in scope (AV:L). One caveat: the tag 'Buffer Overflow' is imprecise - the underlying defect is a use-after-free from missing RCU synchronization, not a classic bounds-write overflow.
Exploit ScenarioDerived

A local unprivileged user runs a program that creates a UDP SO_REUSEPORT group with an attached cBPF steering filter, then in a tight loop replaces the filter via setsockopt() while a second thread floods the port with UDP packets. The receive path in reuseport_select_sock() dereferences the just-freed cBPF program, producing a use-after-free that the attacker can attempt to leverage for kernel memory disclosure, crash (DoS), or privilege escalation via heap grooming. A reproducer that reliably triggers the KASAN out-of-bounds read exists (reported by Eulgyu Kim), though no weaponized public exploit has been identified.
This Week Schedule remediation this week. Why: Active threat signals + CRITICAL/HIGH severity.
Patch available 0.2% exploitation probability (EPSS)

Get an e-mail when this CVE is exploited, patched or re-scored. Free account.

Alert me

AnalysisAIv1 – Jun 28, 2026

Local privilege escalation / memory corruption in the Linux kernel's SO_REUSEPORT BPF handling allows a local user to trigger a use-after-free (vmalloc out-of-bounds read) by replacing a classic BPF (cBPF) reuseport program via setsockopt() while another thread routes UDP traffic through the same reuseport group. Because the cBPF program is freed immediately by sk_reuseport_prog_free() without waiting for an RCU grace period, in-flight readers in reuseport_select_sock() dereference freed memory; the fix defers freeing until after one RCU grace period. No public exploit identified at time of analysis and EPSS probability is low (0.17%), but the bug is confirmed and fixed upstream.

RemediationAI

Vendor-released patch: upgrade to a fixed kernel for your branch - 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94, 6.18.36, or mainline 7.0.13 / 7.1 (or later) - which defers freeing the reuseport cBPF program until after an RCU grace period. Distribution users should track and install the corresponding Debian and Ubuntu kernel security updates rather than building from source; map your running version to the appropriate stable fix commit listed at https://git.kernel.org/stable/c/ (e.g. https://git.kernel.org/stable/c/08264d5bba0bdd3a79bc2984fee09286aba0c4eb) and consult https://nvd.nist.gov/vuln/detail/CVE-2026-52910 and https://vuldb.com/vuln/372370. If patching must be delayed, the practical compensating control is to restrict who can create SO_REUSEPORT sockets and attach reuseport BPF filters - the trigger requires local unprivileged access plus the ability to call setsockopt(SO_ATTACH_REUSEPORT_CBPF) and to send UDP traffic through the group, so limiting untrusted local users, container workloads, and seccomp-restricting the relevant socket options reduces exposure; note this can break legitimate multi-process UDP load-balancing services (e.g. DNS resolvers, QUIC/HTTP3 servers) that rely on cBPF reuseport steering, so test before enforcing. There is no remote network exposure to firewall off, since the attack vector is local.

Affected VersionsENISA

Linux patch: 7.0.13
Linux patch: 5.10.259
Linux 538950a1b7527a0a52ccd9337e3fcd304f027f13 <f8b8f1d4bb76098e87b8269a0631019648330e6d
Linux patch: 6.1.176
Linux 4.5
Linux 538950a1b7527a0a52ccd9337e3fcd304f027f13 <fec41484e7c2aa7ded44c541bba98872be937754
Linux patch: 6.18.36
Linux patch: 0
Linux patch: 6.12.94
Linux 538950a1b7527a0a52ccd9337e3fcd304f027f13 <18fc650ccd7fe3376eca89203668cfb8268f60df
Linux 538950a1b7527a0a52ccd9337e3fcd304f027f13 <298db6167f81e9c470a57cf652e4e47757b4293e
Linux 538950a1b7527a0a52ccd9337e3fcd304f027f13 <c3e3fddda6b5d9ba505d218b4055e7d8a282ac57
Linux patch: 7.1
Linux 538950a1b7527a0a52ccd9337e3fcd304f027f13 <90e47dc5c572d1c73971ac51c7428803f42b78eb
Linux patch: 5.15.210
Linux patch: 6.6.143
Linux 538950a1b7527a0a52ccd9337e3fcd304f027f13 <87dfb977bdb6eaa47e9993a34e18f44970f88b1f
Linux 538950a1b7527a0a52ccd9337e3fcd304f027f13 <08264d5bba0bdd3a79bc2984fee09286aba0c4eb

Affected Packages

euvd linux no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

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

Sign in to check
Technical ContextAI · show details

The flaw lives in the kernel networking stack's socket reuseport facility (net/core/sock_reuseport.c), which lets multiple sockets bind to the same port and uses an attached BPF program to steer incoming packets to a specific socket. Two BPF program types can be attached: 'classic' cBPF (legacy socket filters) and 'extended' eBPF. The receive fast path (reuseport_select_sock -> udp4_lib_lookup2 -> __udp4_lib_rcv) runs under RCU read-side protection and can fire from softirq context. The detach/replace paths reached via setsockopt() (reuseport_attach_prog / reuseport_detach_prog) called sk_reuseport_prog_free(), which for cBPF immediately invokes bpf_release_orig_filter()/bpf_prog_free() with no RCU synchronization, whereas eBPF programs are already torn down through the deferred bpf_prog_put() machinery. The root cause class is a use-after-free / RCU lifetime violation (CWE-416-style, although the CVE lists CWE as N/A and the tags label it 'Buffer Overflow'); KASAN reports it as a vmalloc-out-of-bounds read of the freed JIT/filter buffer. Per the CPE data the affected component is the Linux kernel itself (cpe:2.3:a:linux:linux:*).

Know when the next one hits your stack

  • Watch products and get an email when something new is published
  • Check this CVE against your own stack and servers
  • Exploit and PoC references, threat intelligence from 22 sources
Continue with Google Continue with GitHub

No credit card · 7-day full trial

Severity by source

Vendor (Linux) PRIMARY 7.8 HIGH
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
vuln.today AI 7.0 HIGH

Local low-priv user can trigger via standard socket syscalls (AV:L/PR:L), but it is a race condition requiring a timing window, so AC:H; UAF enables memory disclosure and EoP (C/I/A:H).

3.1 AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
4.0 AV:L/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
SUSE 5.3 MEDIUM
AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:H
Red Hat 6.4 MEDIUM

Primary rating from Vendor (Linux).

CVSS VectorVendor: Linux

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

Lifecycle Timeline

4
CVSS changed
Jun 28, 2026 - 08:22 NVD
7.8 (HIGH)
Patch available
Jun 19, 2026 - 16:01 EUVD
CVE Published
Jun 19, 2026 - 14:43 cve.org
UNKNOWN (no severity yet)
CVE Published
Jun 19, 2026 - 14:43 cve.org
HIGH 7.8

DescriptionCVE.org

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

bpf: Free reuseport cBPF prog after RCU grace period.

Eulgyu Kim reported the splat below with a repro. [0]

The repro sets up a UDP reuseport group with a cBPF prog and replaces it with a new one while another thread is sending a UDP packet to the group.

The reuseport prog is freed by sk_reuseport_prog_free(). bpf_prog_put() is called for "e"BPF prog to destruct through multiple stages while cBPF prog is freed immediately by bpf_release_orig_filter() and bpf_prog_free().

If a reuseport prog is detached from the setsockopt() path (reuseport_attach_prog() or reuseport_detach_prog()), sk_reuseport_prog_free() is called without waiting for RCU readers to complete, resulting in various bugs.

Let's defer freeing the reuseport cBPF prog after one RCU grace period.

Note "e"BPF prog is safe as is unless the fast path starts to touch fields destroyed in bpf_prog_put_deferred() and __bpf_prog_put_noref().

[0]: BUG: KASAN: vmalloc-out-of-bounds in reuseport_select_sock+0xedc/0x1220 net/core/sock_reuseport.c:596 Read of size 4 at addr ffffc9000051e004 by task slowme/10208 CPU: 6 UID: 1000 PID: 10208 Comm: slowme Not tainted 7.0.0-geb7ac95ff75e #32 PREEMPT(full) Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: <IRQ> dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xca/0x240 mm/kasan/report.c:482 kasan_report+0x118/0x150 mm/kasan/report.c:595 reuseport_select_sock+0xedc/0x1220 net/core/sock_reuseport.c:596 udp4_lib_lookup2+0x3bc/0x950 net/ipv4/udp.c:495 __udp4_lib_lookup+0x768/0xe20 net/ipv4/udp.c:723 __udp4_lib_lookup_skb+0x297/0x390 net/ipv4/udp.c:752 __udp4_lib_rcv+0x1312/0x2620 net/ipv4/udp.c:2752 ip_protocol_deliver_rcu+0x282/0x440 net/ipv4/ip_input.c:207 ip_local_deliver_finish+0x3bb/0x6f0 net/ipv4/ip_input.c:241 NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318 NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318 __netif_receive_skb_one_core net/core/dev.c:6181 [inline] __netif_receive_skb net/core/dev.c:6294 [inline] process_backlog+0xaa4/0x1960 net/core/dev.c:6645 __napi_poll+0xae/0x340 net/core/dev.c:7709 napi_poll net/core/dev.c:7772 [inline] net_rx_action+0x5d7/0xf50 net/core/dev.c:7929 handle_softirqs+0x22b/0x870 kernel/softirq.c:622 do_softirq+0x76/0xd0 kernel/softirq.c:523 </IRQ> <TASK> __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:924 [inline] __dev_queue_xmit+0x1dd7/0x3710 net/core/dev.c:4890 neigh_output include/net/neighbour.h:556 [inline] ip_finish_output2+0xca9/0x1070 net/ipv4/ip_output.c:237 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip_output+0x29f/0x450 net/ipv4/ip_output.c:438 ip_send_skb+0x45/0xc0 net/ipv4/ip_output.c:1508 udp_send_skb+0xb04/0x1510 net/ipv4/udp.c:1195 udp_sendmsg+0x1a71/0x2350 net/ipv4/udp.c:1485 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] __sys_sendto+0x554/0x680 net/socket.c:2206 __do_sys_sendto net/socket.c:2213 [inline] __se_sys_sendto net/socket.c:2209 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2209 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x160/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x415a2d Code: b3 66 2e 0f 1f 84 00 00 00 00 00 66 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f6bc31e41e8 EFLAGS: 00000212 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f6bc31e4cdc RCX: 0000000000415a2d RDX: 0000000000000001 RSI: 00007f6bc31e421f RDI: 0000000000000003 RBP: 00007f6bc31e4240 R08: 00007f6bc31e4220 R09: 0000000000000010 R10: 0000000000000000 R11: ---truncated---

Executive ViewAI

Why It Matters

A local privilege escalation vulnerability in Linux kernels (CVE-2026-52910) could allow unprivileged users to gain unauthorized access to system-level operations on affected machines. Organizations running shared Linux infrastructure, containerized platforms, or systems with multiple local users face risk of unauthorized privilege escalation and potential data compromise. Currently, no public exploit has been identified; vendor patches are available.

Business Impact: High
Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score
0.2%
Top 94% exploitable
Prevalence
Ubiquitous
Linux kernel runs across the vast majority of server and cloud environments
Threat Intel
2
1 sources
Data Quality
6 sources
Confidence: High
EUVD NVD CVE.org EPSS CISA MSRC Vendor VulDB

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 HIGH
CISA KEV No
Public POC No
EPSS 0.2%
Patch available Yes
Active threat Yes
Deciding rule
Active threat signals + CRITICAL/HIGH severity
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
Scheduled
Exploitation· derived
None
System Exposure· derived
Small
Automatable· derived
No
Human Impact
High

Priority Score

49
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +39
PoC: 0
Weaponized: 0
Threat intel: +10
Gov advisory: 0

Attack Technique

Buffer Overflow HIGH

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

Same weakness CWE-364 – Signal Handler Race Condition

View all
CVE-2024-6387 HIGH POC
8.1
CVE-2024-6409 HIGH
7.0
CVE-2025-4598 MEDIUM POC
4.7
CVE-2026-24792 HIGH
8.1
CVE-2026-53185 HIGH
7.8
CVE-2026-42002 HIGH
7.5
CVE-2023-5676 MEDIUM
5.9
CVE-2023-1285 MEDIUM
5.9

Same technique Buffer Overflow

View all
CVE-2017-7269 CRITICAL POC
9.8
CVE-2015-5119 CRITICAL POC
9.8
CVE-2015-3113 CRITICAL POC
9.8
CVE-2011-2462 CRITICAL POC
9.8
CVE-2020-0796 CRITICAL POC
10.0
CVE-2019-11043 CRITICAL POC
9.8
CVE-2009-0927 HIGH POC
8.8
CVE-2012-1889 HIGH POC
8.8

Vendor StatusVendor

SUSE

Severity: Moderate
Product Status
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 16.0 Affected

Threat IntelligenceMISP

CISA Advisories
ICSA-26-295-11 ICSA-26-295-16
Sources: Microsoft MSRC, CISA (public domain)

References

Advisories & patches
ADVISORY https://nvd.nist.gov/vuln/detail/CVE-2026-52910 ADVISORY https://ubuntu.com/security/notices/USN-8726-1 ADVISORY https://ubuntu.com/security/notices/USN-8727-1 ADVISORY https://vuldb.com/vuln/372370 REF https://access.redhat.com/security/cve/CVE-2026-52910 REF https://bugzilla.redhat.com/show_bug.cgi?id=2490779 REF https://cert-portal.siemens.com/productcert/html/ssa-019113.html REF https://cert-portal.siemens.com/productcert/html/ssa-457936.html REF https://cert-portal.siemens.com/productcert/html/ssa-784472.html REF https://git.kernel.org/stable/c/08264d5bba0bdd3a79bc2984fee09286aba0c4eb REF https://git.kernel.org/stable/c/18fc650ccd7fe3376eca89203668cfb8268f60df REF https://git.kernel.org/stable/c/298db6167f81e9c470a57cf652e4e47757b4293e REF https://git.kernel.org/stable/c/87dfb977bdb6eaa47e9993a34e18f44970f88b1f REF https://git.kernel.org/stable/c/90e47dc5c572d1c73971ac51c7428803f42b78eb REF https://git.kernel.org/stable/c/c3e3fddda6b5d9ba505d218b4055e7d8a282ac57 REF https://git.kernel.org/stable/c/f8b8f1d4bb76098e87b8269a0631019648330e6d REF https://git.kernel.org/stable/c/fec41484e7c2aa7ded44c541bba98872be937754 REF https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52910.json

Search Externally

GitHub PoC Exploit-DB PacketStorm Snyk Rapid7 Nuclei Templates Trickest PoC
Back

This site uses cookies essential for authentication and security. No tracking or analytics cookies are used. Privacy Policy