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VulnerabilityPublished Updated

CVE-2026-45957: Linux kernel · rcu: Fix rcu_read_unlock() deadloop due to softirq

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in d41e37f26b3157b3f1d10223863519a943aa239b : patch Linux kernel soon.

Data as of 30 Oct 2026, 12:36 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
Patch
Available – fixed in d41e37f26b3157b3f1d10223863519a943aa239b, d36d8a7cf0e1d52ccde290855782b7b2ffc78f63, c2932e16d8c354404b17123e64daa8e33191e145 +3

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 27 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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 30 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 5f5fa7ea89dc82d34ed458f4d7a8634e8e9eefce, < d41e37f26b3157b3f1d10223863519a943aa239b
Fixed in
  • d41e37f26b3157b3f1d10223863519a943aa239b
LinuxLinuxAffected
  • ≥ 5f5fa7ea89dc82d34ed458f4d7a8634e8e9eefce, < d36d8a7cf0e1d52ccde290855782b7b2ffc78f63
Fixed in
  • d36d8a7cf0e1d52ccde290855782b7b2ffc78f63
LinuxLinuxAffected
  • ≥ 5f5fa7ea89dc82d34ed458f4d7a8634e8e9eefce, < c2932e16d8c354404b17123e64daa8e33191e145
Fixed in
  • c2932e16d8c354404b17123e64daa8e33191e145
LinuxLinuxAffected
  • ≥ 5f5fa7ea89dc82d34ed458f4d7a8634e8e9eefce, < 979c708e6c9d7fc461daef2dad8b45f22e23464c
Fixed in
  • 979c708e6c9d7fc461daef2dad8b45f22e23464c
LinuxLinuxAffected
  • ≥ 5f5fa7ea89dc82d34ed458f4d7a8634e8e9eefce, < 4a4a6e12c9c829be3f74b7206fa8640fc4e1c566
Fixed in
  • 4a4a6e12c9c829be3f74b7206fa8640fc4e1c566
LinuxLinuxAffected
  • ≥ 5f5fa7ea89dc82d34ed458f4d7a8634e8e9eefce, < 1f16679a5aa60238466ce339c35f5e82ece60337
Fixed in
  • 1f16679a5aa60238466ce339c35f5e82ece60337

AI-suggested

A fix for this vulnerability is available in the Linux kernel. The issue was resolved by commits that set a defer_qs_pending flag before calling raise_softirq_irqoff(). Users should update to a fixed kernel version containing these commits to mitigate the issue.

Description

CVE-2026-45957 is a vulnerability in the Linux kernel affecting version 5.8 where the rcu_read_unlock() function could enter an infinite deadloop due to issues with softirq handling and recursion protection removal. This was caused by a change that removed recursion-protection code, leading to a deadloop in raise_softirq_irqoff() when ftrace is enabled. The issue was fixed by setting a flag before calling raise_softirq_irqoff() to prevent the deadloop.

References

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