CVE-2025-39965: Linux kernel · xfrm: xfrm_alloc_spi shouldn't use 0 as SPI
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 7.8 High · fixed in cd8ae32e4e4652db55bce6b9c79267d8946765a9 : patch Linux kernel soon.
Data as of 30 Oct 2026, 13:32 UTC
Thin evidence
One scorer or none| CNA (Linux) | CVSS 3.1 | 7.8 |
|---|
- 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, 2026-10-15.
- Patch
- Available – fixed in cd8ae32e4e4652db55bce6b9c79267d8946765a9, a78e55776522373c446f18d5002a8de4b09e6bf7, 9fcedabaae0096f712bbb4ccca6a8538af1cd1c8 +6
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 13 Oct 2025
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 30 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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AI-suggested
This vulnerability has been fixed in Linux kernel versions 6.2, 6.6.109, 6.12.50, 6.16, and 6.16.10, among others. Users and administrators should upgrade to these or later kernel versions to remediate the issue. No additional mitigation steps are indicated by the vendor advisory.
Description
CVE-2025-39965 is a high-severity vulnerability in the Linux kernel's xfrm subsystem where the function xfrm_alloc_spi incorrectly uses 0 as a Security Parameter Index (SPI). This leads to states being created and added to the byspi list with an invalid SPI value of 0, which should indicate 'no SPI assigned'. The deletion function __xfrm_state_delete does not remove these states from the list, causing a use-after-free (UAF) condition on subsequent accesses.
References
- git.kernel.org/stable/c/0baf92d0b1590b903c1f4ead75e61715e50e8146 (opens in a new tab)
- git.kernel.org/stable/c/9fcedabaae0096f712bbb4ccca6a8538af1cd1c8 (opens in a new tab)
- git.kernel.org/stable/c/a78e55776522373c446f18d5002a8de4b09e6bf7 (opens in a new tab)
- git.kernel.org/stable/c/cd8ae32e4e4652db55bce6b9c79267d8946765a9 (opens in a new tab)