VulnerabilityPublished 24 Apr 2026Updated 5 Nov 2026

CVE-2026-31580: Linux kernel · bcache: fix cached_dev.sb_bio use-after-free and crash

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in fec114a98b8735ee89c75216c45a78e28be0f128 : patch Linux kernel soon.

Data as of 5 Nov 2026, 22:05 UTC

Severity

High

Rated High by Threat Radar's AI analysis · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-11-05.

Patch

Available – fixed in fec114a98b8735ee89c75216c45a78e28be0f128, f50e7c325ab1207fe941555bcff659f6d7050572, add4982510f3b7c318a2dd7438bdc9c63171e753 +6

Exploitation evidence

Disclosed: evidence found.
CVE published 24 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ cafe563591446cf80bfbc2fe3bc72a2e36cf1060, < fec114a98b8735ee89c75216c45a78e28be0f128	Fixed in fec114a98b8735ee89c75216c45a78e28be0f128
LinuxLinux	Affected ≥ cafe563591446cf80bfbc2fe3bc72a2e36cf1060, < f50e7c325ab1207fe941555bcff659f6d7050572	Fixed in f50e7c325ab1207fe941555bcff659f6d7050572
LinuxLinux	Affected ≥ cafe563591446cf80bfbc2fe3bc72a2e36cf1060, < add4982510f3b7c318a2dd7438bdc9c63171e753	Fixed in add4982510f3b7c318a2dd7438bdc9c63171e753
LinuxLinux	Affected ≥ cafe563591446cf80bfbc2fe3bc72a2e36cf1060, < 9467d360be70e6ee55b0c1cd2a1f1424f57b5b85	Fixed in 9467d360be70e6ee55b0c1cd2a1f1424f57b5b85
LinuxLinux	Affected ≥ cafe563591446cf80bfbc2fe3bc72a2e36cf1060, < 383f7fec0de8cee1cf7ae1f9d9f14044a61f10f9	Fixed in 383f7fec0de8cee1cf7ae1f9d9f14044a61f10f9
LinuxLinux	Affected ≥ cafe563591446cf80bfbc2fe3bc72a2e36cf1060, < 81f44ed8c3f54abb7561ece774ea4cca5070b2f2	Fixed in 81f44ed8c3f54abb7561ece774ea4cca5070b2f2

AI-suggested

A fix is available and has been applied in multiple Linux kernel commits. Users should update their Linux kernel to a version that includes these fixes to prevent the use-after-free and associated crashes. No additional mitigation steps are indicated or required beyond applying the official patch.

Description

CVE-2026-31580 is a use-after-free vulnerability in the Linux kernel's bcache subsystem affecting version 3.10. The flaw involves the cached_dev.sb_bio structure being accessed after it has been freed, leading to kernel crashes. This occurs if the device is stopped while writing to the superblock, causing the released memory to be accessed during endio operations. The issue has been fixed by ensuring that sb_write completes before freeing cached_dev.

Impact

The vulnerability can cause kernel crashes due to use-after-free memory access in the bcache subsystem. This can lead to system instability and potential denial of service on affected Linux systems running version 3.10. There is no indication of code execution or privilege escalation from the provided data.

Summary

This vulnerability in the Linux kernel bcache module involves a use-after-free condition on cached_dev.sb_bio, a member of the cached_dev structure. The problem arises when the device is stopped during a superblock write operation, and the sb_bio memory is freed prematurely. Kernel crash logs from libceph-related components indicate attempts to access freed memory, causing instability. The fix involves waiting for the sb_write operation to complete before freeing cached_dev, preventing access to freed memory and subsequent crashes. Multiple commits have addressed this issue in the kernel source.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 5 Nov 2026, 22:05 UTC

Technical details

References

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