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VulnerabilityPublished Updated

CVE-2026-63830: Linux kernel · net: skmsg: preserve sg.copy across SG transforms

Affects Linux kernelSource GCVE Database

0
Authoritative record:CVE-2026-63830· Critical 9.4

Not known to be exploited · CVSS 9.4 Critical · fixed in 5.15.0-1117.124~20.04.1 : patch Linux kernel as a priority.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score
9.4Critical
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.4% chance of exploitation in 30 days – higher than 38% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 5.15.0-1117.124~20.04.1, 5.15.0-1123.132~20.04.1, 5.15.0-1122.131~20.04.1 +44
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 19 Jul 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
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threatsAffected
  • <7.0.0-31.31
Fixed in
  • 7.0.0-31.31
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threatsAffected
  • <7.0.0-1012.12
Fixed in
  • 7.0.0-1012.12
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threatsAffected
  • <7.0.0-1014.14
Fixed in
  • 7.0.0-1014.14
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threatsAffected
  • 7.0.0-1003.3 – 7.0.0-1016.16
9 affected builds
Fixed in–
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threatsAffected
  • <7.0.0-1011.11
Fixed in
  • 7.0.0-1011.11
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threatsAffected
  • <7.0.0-1006.7
Fixed in
  • 7.0.0-1006.7

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available for this vulnerability and should be applied promptly. The vendor advisory from Ubuntu confirms that fixes have been released in updated Linux kernel packages. After applying the update, a system reboot is required. Additionally, due to ABI changes, third-party kernel modules must be recompiled and reinstalled. Follow the vendor's update instructions to ensure complete remediation.

Description

A vulnerability in the Linux kernel's sk_msg subsystem could allow BPF programs to write to memory pages that should be protected, due to improper handling of the sg.copy bitmap during scatterlist transformations. This flaw could lead to unauthorized modification of original page cache memory. The issue affects multiple Linux kernel versions and has been addressed by synchronizing the sg.copy bitmap with data entries during transformations. A patch is available and should be applied to mitigate the risk.

References

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