CVE-2026-23410: Linux kernel · apparmor: fix race on rawdata dereference
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 4.15.0-1200.215~14.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 4.15.0-1200.215~14.04.1, 4.15.0-1191.204~16.04.1, 4.15.0-1200.215~16.04.1 +108
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 1 Apr 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 25.10linuxpkg:deb/ubuntu/linux@6.17.0-19.19?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws@6.17.0-1009.9?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure@6.17.0-1010.10?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde@6.17.0-1017.17?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-gcppkg:deb/ubuntu/linux-gcp@6.17.0-1009.9?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle@6.17.0-1009.9?arch=source&distro=questingOther 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 should be applied promptly. The vendor advisory from Ubuntu recommends updating the Linux kernel packages to the fixed versions listed for the affected Ubuntu releases. After updating, a system reboot is required to apply the fixes. Due to ABI changes, recompilation and reinstallation of third-party kernel modules may be necessary. Following the vendor's official update instructions will mitigate this vulnerability effectively.
Description
A race condition vulnerability in the Linux kernel's AppArmor security module (CVE-2026-23410) has been resolved. The flaw involves a use-after-free situation caused by improper reference counting of rawdata inodes, which can lead to freed memory being accessed. This issue could be triggered by an attacker opening a rawdata file while simultaneously removing the last reference to it, causing a dangling pointer dereference. The fix involves implementing a double reference counting scheme to prevent the race condition. This vulnerability affects multiple specific versions of the Linux Azure kernel and has a high severity score. A patch is available and should be applied to mitigate the risk.
References
- ubuntu.com/security/CVE-2026-23410 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-23410 (opens in a new tab)
- ubuntu.com/blog/apparmor-vulnerability-fixes-available (opens in a new tab)
- ubuntu.com/security/vulnerabilities/crackarmor (opens in a new tab)
- cdn2.qualys.com/advisory/2026/03/10/crack-armor.txt (opens in a new tab)
- openwall.com/lists/oss-security/2026/04/01/3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8152-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8163-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8164-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8165-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8163-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8098-10 (opens in a new tab)
- ubuntu.com/security/notices/USN-8201-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8224-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8243-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8261-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8266-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8267-1 (opens in a new tab)