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VulnerabilityPublished Updated

CVE-2026-43501: Linux kernel · ipv6: rpl: reserve mac_len headroom when recompressed SRH grows

Source GCVE Database

0
Authoritative record:CVE-2026-43501· Critical 9.8

Not known to be exploited · CVSS 9.8 Critical · fixed in c261d07a80576dc8ccf394ef8f074f8c67a06b37 : patch Linux kernel as a priority.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score
9.8Critical
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.7% chance of exploitation in 30 days – higher than 54% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in c261d07a80576dc8ccf394ef8f074f8c67a06b37, be1fa0aa9b4fdd5a8b7a61ba520a690a68391e6e, bde199c72d319a4e207f88daabc888317504e2fb +5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 21 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
  • ≥ 8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3, < c261d07a80576dc8ccf394ef8f074f8c67a06b37
Fixed in
  • c261d07a80576dc8ccf394ef8f074f8c67a06b37
LinuxLinuxAffected
  • ≥ 8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3, < be1fa0aa9b4fdd5a8b7a61ba520a690a68391e6e
Fixed in
  • be1fa0aa9b4fdd5a8b7a61ba520a690a68391e6e
LinuxLinuxAffected
  • ≥ 8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3, < bde199c72d319a4e207f88daabc888317504e2fb
Fixed in
  • bde199c72d319a4e207f88daabc888317504e2fb
LinuxLinuxAffected
  • ≥ 8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3, < 7398ebefbfd4f8a31d4f665a4213302fa995494b
Fixed in
  • 7398ebefbfd4f8a31d4f665a4213302fa995494b
LinuxLinuxAffected
  • ≥ 8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3, < 9e6bf146b55999a095bb14f73a843942456d1adc
Fixed in
  • 9e6bf146b55999a095bb14f73a843942456d1adc
LinuxLinuxAffected
  • ≥ 8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3, < 8e8be63465a5e80394c70324603dfea1bfdad48f
Fixed in
  • 8e8be63465a5e80394c70324603dfea1bfdad48f

AI-suggested

A fix is available from Red Hat as a kernel update for Red Hat Enterprise Linux 9 and 10 and Red Hat In-Vehicle OS 2. Systems should apply the updated kernel packages and reboot to remediate the vulnerability. As a temporary mitigation, administrators can disable IPv6 Source Routing by setting the sysctl parameters net.ipv6.conf.all.accept_source_route=0 and net.ipv6.conf.default.accept_source_route=0. This prevents the kernel from processing IPv6 Source Routing Headers and avoids the vulnerable code path. Note that disabling IPv6 Source Routing may impact network configurations relying on this feature.

Description

A critical vulnerability (CVE-2026-43501) in the Linux kernel's IPv6 Source Routing Header (SRH) recompression process allows a local attacker to trigger an out-of-bounds write due to insufficient reserved headroom. This memory corruption can lead to denial of service or potentially arbitrary code execution. The flaw affects Red Hat Enterprise Linux 9 and 10, and Red Hat In-Vehicle OS 2. A patch is available from Red Hat, and a mitigation involves disabling IPv6 Source Routing by setting the accept_source_route sysctl parameter to 0. Systems should apply the vendor-provided kernel update and reboot to remediate the issue.

References

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