CVE-2026-63827: Linux kernel · apparmor: fix use-after-free in rawdata dedup loop
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 5.15.0-1117.124~20.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% 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:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 19 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
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 and included in updated Linux kernel packages for affected Ubuntu and Azure kernel versions. Users should update their systems to the fixed kernel versions and reboot to apply the changes. Due to an ABI change, third-party kernel modules must be recompiled and reinstalled after updating. No additional mitigations are specified by the vendor.
Description
A use-after-free vulnerability in the Linux kernel's AppArmor security module was fixed. The flaw involved improper reference counting in the rawdata deduplication loop within aa_replace_profiles(), which could lead to use-after-free conditions and refcount hardening warnings. This issue was reproduced on x86_64 systems running Ubuntu 24.04. The vulnerability affects multiple Linux kernel versions including various Azure and Ubuntu kernel builds. A patch is available and included in recent kernel updates.
References
- nvd.nist.gov/vuln/detail/CVE-2026-63827 (opens in a new tab)
- git.kernel.org/stable/c/15fd83a1e42ede15070968806bb6c8b1a5170688 (opens in a new tab)
- git.kernel.org/stable/c/5e34fa9f6f7cd688ae153fff13139a5cf2d42339 (opens in a new tab)
- git.kernel.org/stable/c/6f060496d03e4dc560a40f73770bd08335cb7a27 (opens in a new tab)
- git.kernel.org/stable/c/a7a2890028f16e5b0af0bb005d80fcb32559cca3 (opens in a new tab)
- git.kernel.org/stable/c/c3ca2631073b2cef06824fd2bfc452ff7a1023de (opens in a new tab)
- git.kernel.org/stable/c/ce261a20b41db522e320a41bbf1292bf85af66df (opens in a new tab)
- ubuntu.com/security/CVE-2026-63827 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-63827 (opens in a new tab)
- git.kernel.org/linus/6f060496d03e4dc560a40f73770bd08335cb7a27 (opens in a new tab)
- msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-63827.json (opens in a new tab)
- support.microsoft.com/lifecycle (opens in a new tab)
- first.org/cvss (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8727-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8760-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8800-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8760-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8876-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8878-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8879-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8877-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8875-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8886-1 (opens in a new tab)