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VulnerabilityPublished Updated

CVE-2026-43139: Linux kernel · xfrm6: fix uninitialized saddr in xfrm6_get_saddr()

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 8.6 High · fixed in eb2ee15290af14c60b45cf2b73f5687d1d077d9b : patch Linux kernel soon.

Data as of 26 Oct 2026, 15:59 UTC

CVSS 3.1 base score
8.6High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 31% 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 can reliably automate steps 1–4 of the kill chain
Technical impact
Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in eb2ee15290af14c60b45cf2b73f5687d1d077d9b, dc0abce055134cb83b0d981d31ceb20dda419787, c7221e7bd8fc2ef38a0b27be580d9d202281306b +5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 6 May 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
  • ≥ a1e59abf824969554b90facd44a4ab16e265afa4, < eb2ee15290af14c60b45cf2b73f5687d1d077d9b
Fixed in
  • eb2ee15290af14c60b45cf2b73f5687d1d077d9b
LinuxLinuxAffected
  • ≥ a1e59abf824969554b90facd44a4ab16e265afa4, < dc0abce055134cb83b0d981d31ceb20dda419787
Fixed in
  • dc0abce055134cb83b0d981d31ceb20dda419787
LinuxLinuxAffected
  • ≥ a1e59abf824969554b90facd44a4ab16e265afa4, < c7221e7bd8fc2ef38a0b27be580d9d202281306b
Fixed in
  • c7221e7bd8fc2ef38a0b27be580d9d202281306b
LinuxLinuxAffected
  • ≥ a1e59abf824969554b90facd44a4ab16e265afa4, < 6535867673bf301d52aa00593a4d1d18cc3922fa
Fixed in
  • 6535867673bf301d52aa00593a4d1d18cc3922fa
LinuxLinuxAffected
  • ≥ a1e59abf824969554b90facd44a4ab16e265afa4, < 719918fc88df6da023dfff370cd965151a5afd7f
Fixed in
  • 719918fc88df6da023dfff370cd965151a5afd7f
LinuxLinuxAffected
  • ≥ a1e59abf824969554b90facd44a4ab16e265afa4, < 1799d8abeabc68ec05679292aaf6cba93b343c05
Fixed in
  • 1799d8abeabc68ec05679292aaf6cba93b343c05

AI-suggested

A fix is available and has been applied in multiple commits identified by their hashes. Users running Linux kernel version 2.6.19 should update to a fixed version containing these commits to remediate the issue. No additional mitigation steps are indicated by the vendor advisory.

Description

CVE-2026-43139 is a high-severity vulnerability in the Linux kernel affecting version 2.6.19. It involves the xfrm6_get_saddr() function failing to check the return value of ipv6_dev_get_saddr(), which can leave the source address uninitialized. This uninitialized value is then used by subsequent functions, causing a kernel memory sanitizer (KMSAN) warning and potentially leading to undefined behavior or system instability. The issue has been fixed by adding proper error checking and propagation of the failure from ipv6_dev_get_saddr().

References

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