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VulnerabilityPublished Updated

CVE-2026-43186: Linux kernel · ipv6: ioam: fix heap buffer overflow in __ioam6_fill_trace_data()

Source GCVE Database

0
Authoritative record:CVE-2026-43186· Critical 9.8

Not known to be exploited · CVSS 9.8 Critical · fixed in fb3c662fafebc5b9d74417ed1de8759f6bb72143 : patch Linux kernel as a priority.

Data as of 27 Oct 2026, 00:07 UTC

CVSS 3.1 base score
9.8Critical
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in fb3c662fafebc5b9d74417ed1de8759f6bb72143, f4d9d4b8fd839719d564651671e24c62c545c23b, ea3632aefc04205436868541638e26f4a74d5637 +4
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 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
  • ≥ 9ee11f0fff205b4b3df9750bff5e94f97c71b6a0, < fb3c662fafebc5b9d74417ed1de8759f6bb72143
Fixed in
  • fb3c662fafebc5b9d74417ed1de8759f6bb72143
LinuxLinuxAffected
  • ≥ 9ee11f0fff205b4b3df9750bff5e94f97c71b6a0, < f4d9d4b8fd839719d564651671e24c62c545c23b
Fixed in
  • f4d9d4b8fd839719d564651671e24c62c545c23b
LinuxLinuxAffected
  • ≥ 9ee11f0fff205b4b3df9750bff5e94f97c71b6a0, < ea3632aefc04205436868541638e26f4a74d5637
Fixed in
  • ea3632aefc04205436868541638e26f4a74d5637
LinuxLinuxAffected
  • ≥ 9ee11f0fff205b4b3df9750bff5e94f97c71b6a0, < e90346a2f1e8917d5760a44a1f61c44e3b36d96b
Fixed in
  • e90346a2f1e8917d5760a44a1f61c44e3b36d96b
LinuxLinuxAffected
  • ≥ 9ee11f0fff205b4b3df9750bff5e94f97c71b6a0, < 632d233cf2e64a46865ae2c064ae3c9df7c8864f
Fixed in
  • 632d233cf2e64a46865ae2c064ae3c9df7c8864f
LinuxLinuxAffected
  • ≥ 9ee11f0fff205b4b3df9750bff5e94f97c71b6a0, < 0591d6509c2ff13f09ea2998434aba0c0472e978
Fixed in
  • 0591d6509c2ff13f09ea2998434aba0c0472e978

Description

In the Linux kernel, the following vulnerability has been resolved: ipv6: ioam: fix heap buffer overflow in __ioam6_fill_trace_data() On the receive path, __ioam6_fill_trace_data() uses trace->nodelen to decide how much data to write for each node. It trusts this field as-is from the incoming packet, with no consistency check against trace->type (the 24-bit field that tells which data items are present). A crafted packet can set nodelen=0 while setting type bits 0-21, causing the function to write ~100 bytes past the allocated region (into skb_shared_info), which corrupts adjacent heap memory and leads to a kernel panic. Add a shared helper ioam6_trace_compute_nodelen() in ioam6.c to derive the expected nodelen from the type field, and use it: - in ioam6_iptunnel.c (send path, existing validation) to replace the open-coded computation; - in exthdrs.c (receive path, ipv6_hop_ioam) to drop packets whose nodelen is inconsistent with the type field, before any data is written. Per RFC 9197, bits 12-21 are each short (4-octet) fields, so they are included in IOAM6_MASK_SHORT_FIELDS (changed from 0xff100000 to 0xff1ffc00).

References

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