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VulnerabilityPublished Updated

CVE-2026-89580: Linux kernel · bpf: Disable preemption in __bpf_get_stack

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in dbfecc8a6631c0d3626c14ba1f1a485a4498445a : patch Linux kernel soon.

Data as of 26 Oct 2026, 13:07 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
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
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in dbfecc8a6631c0d3626c14ba1f1a485a4498445a, b1a47b2708d4e95dbd23aee2ec83752190897b3f, 719e69421de28829c72bf8a2722ab48a1c5a59ad +2
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 11 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: 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 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ c195651e565ae7f41a68acb7d4aa7390ad215de1, < dbfecc8a6631c0d3626c14ba1f1a485a4498445a
Fixed in
  • dbfecc8a6631c0d3626c14ba1f1a485a4498445a
LinuxLinuxAffected
  • ≥ c195651e565ae7f41a68acb7d4aa7390ad215de1, < b1a47b2708d4e95dbd23aee2ec83752190897b3f
Fixed in
  • b1a47b2708d4e95dbd23aee2ec83752190897b3f
LinuxLinuxAffected
  • ≥ c195651e565ae7f41a68acb7d4aa7390ad215de1, < 719e69421de28829c72bf8a2722ab48a1c5a59ad
Fixed in
  • 719e69421de28829c72bf8a2722ab48a1c5a59ad
LinuxLinuxAffected
  • ≥ c195651e565ae7f41a68acb7d4aa7390ad215de1, < 9a23747909fcae707990c8466c381a0e7acfaa4e
Fixed in
  • 9a23747909fcae707990c8466c381a0e7acfaa4e
LinuxLinuxAffected
  • ≥ c195651e565ae7f41a68acb7d4aa7390ad215de1, < 8c5ba022f2085ea42d011497a6e92e527d123b9b
Fixed in
  • 8c5ba022f2085ea42d011497a6e92e527d123b9b
LinuxLinuxAffected
  • =4.18
Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Disable preemption in __bpf_get_stack get_perf_callchain() returns a per-CPU perf_callchain_entry buffer and releases its recursion slot via put_callchain_entry() before returning, so nothing keeps the entry reserved while __bpf_get_stack() consumes it below. A preemptible BPF program (e.g. a non-sleepable raw tracepoint program on a PREEMPT kernel, which runs under migrate_disable() but not preempt_disable()) can be scheduled out between obtaining the entry and the copy. Another task scheduled on the same CPU then reuses the same per-CPU buffer and overwrites trace->nr with a larger value. copy_len is then computed from the inflated trace->nr and can exceed the caller's buffer, causing an out-of-bounds write in the memcpy() and in the build_id path. The rcu_read_lock() taken here alone does not prevent this. It is only taken on the may_fault path, and under CONFIG_PREEMPT_RCU it does not disable preemption; it merely keeps perf's callchain buffer array alive (freed via call_rcu()) and does nothing to stop another task from reusing the entry. Disable preemption around obtaining the callchain entry and copying it into the caller's buffer, so the entry cannot be reused underneath us and trace->nr stays bounded by max_depth. Build ID resolution may fault and is therefore deferred until after preemption is re-enabled; by then the instruction pointers have already been copied into buf, so it operates only on that private copy. Note, preempt_disable() also subsumes the buffer-lifetime guarantee the rcu_read_lock() provided, since a preempt-disabled section is an RCU read-side critical section for the callchain buffers' call_rcu() reclaim. [ changed Fixes: commit ]

References

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