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Linux Kernel EUVDEUVD-2026-59523

| CVE-2026-74376 CRITICAL
2026-08-15 Linux GHSA-4w7v-gf5r-fhph
Critical
Disputed · 9.8 Vendor: Linux
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Severity by source

Sources disagree (Low–Critical)
Vendor (Linux) PRIMARY
9.8 CRITICAL
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
vuln.today AI
2.5 LOW

Local block-layer access needed (AV:L, PR:L); requires the uncommon race of read-then-discard on a raid10 array with an active replacement device (AC:H); impact is only a gradual memory leak (A:L, no C/I).

3.1 AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
4.0 AV:L/AC:H/AT:P/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Red Hat
5.5 LOW
qualitative

vuln.today treats the vendor’s rating as authoritative. A higher third-party CVSS (e.g. CISA-ADP) is shown for transparency but does not drive the headline severity.

CVSS VectorVendor: Linux

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

5
Analysis Generated
Aug 17, 2026 - 10:53 vuln.today
CVSS changed
Aug 17, 2026 - 06:22 NVD
9.8 (CRITICAL)
Patch available
Aug 15, 2026 - 07:19 EUVD
CVE Published
Aug 15, 2026 - 05:58 cve.org
CRITICAL 9.8
CVE Published
Aug 15, 2026 - 05:58 cve.org
UNKNOWN (no severity yet)

DescriptionCVE.org

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

md/raid10: reset read_slot when reusing r10bio for discard

put_all_bios() always drops devs[i].bio, but it only drops devs[i].repl_bio when r10_bio->read_slot < 0. If discard reuses an r10bio that was previously used for a read, read_slot can still be non-negative, and discard cleanup can skip bio_put() on repl_bio.

Reset read_slot to -1 when preparing an r10bio for discard so the replacement bio is always released correctly.

AnalysisAI

Kernel memory (bio structure) leak in the Linux md/raid10 driver occurs when a discard operation reuses an r10bio object previously used for a read. Because put_all_bios() only releases the replacement bio (repl_bio) when read_slot is negative, a reused r10bio with a stale non-negative read_slot skips the bio_put() on repl_bio, leaking kernel memory on RAID10 arrays that have replacement/spare devices and receive discard (TRIM) traffic. …

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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

Recon
Local access to RAID10 md device with active replacement
Delivery
Submit read I/O setting read_slot
Exploit
Issue discard reusing same r10bio
Install
repl_bio skipped in put_all_bios cleanup
C2
Kernel bio leaked per operation
Execute
Sustained discard exhausts memory
Impact
Denial of service

Vulnerability AssessmentAI

Exploitation Exploitation requires the target to be running Linux software RAID (md) with the raid10 personality AND to have discard/TRIM enabled on that array, AND for the array to have an active replacement/spare device so that repl_bio is allocated - without a replacement device there is no repl_bio to leak. … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment The signals conflict sharply and the published CVSS 9.8 should not be trusted at face value. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario A local user or workload on a server whose storage is a Linux software RAID10 array with an in-progress device replacement repeatedly issues reads followed by discard/TRIM operations (e.g., normal filesystem activity plus periodic fstrim). Each discard that reuses a read-tagged r10bio leaks one bio, and sustained activity slowly exhausts kernel memory until the system degrades or an OOM condition triggers a denial of service. …
Remediation Patch available per vendor advisory - upgrade to a fixed stable kernel for your branch: 5.15.212, 6.1.178, 6.6.145, 6.12.97, 7.1.5, or 6.18.40 (or later), which reset read_slot to -1 before discard so repl_bio is always released (see the stable commits at https://git.kernel.org/stable/c/561c9711e4f545d6464a023168bdee03b00fa945 and siblings). … Detailed patch versions, workarounds, and compensating controls in full report.

Recommended ActionAI

Within 24 hours, inventory Linux systems using RAID10 arrays with replacement or spare devices. …

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Threat intelligence, references, and detailed analysis are available after sign-in.

Vendor StatusVendor

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EUVD-2026-59523 vulnerability details – vuln.today

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