CVE-2026-53273: Linux kernel · tee: optee: prevent use-after-free when the client exits before the supplicant
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, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 4% 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 +70
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 25 Jun 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 fixed versions include Linux kernel 5.15.0-1117.124~20.04.1 and later. Users should upgrade to these or later fixed kernel versions to remediate the vulnerability. No additional mitigations are required as the fix addresses the root cause by serializing access to the request and preventing premature freeing.
Description
A use-after-free vulnerability in the Linux kernel's OP-TEE Trusted Execution Environment driver (tee: optee) was resolved. The flaw occurs when a client task exits before the supplicant finishes processing its request, leading to dereferencing freed memory. This was caused by a race condition introduced by a commit that allowed the client to terminate while the supplicant was still active. The fix serializes access to the request using a mutex to prevent the race condition and eliminate the use-after-free.
References
- ubuntu.com/security/CVE-2026-53273 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-53273 (opens in a new tab)
- git.kernel.org/linus/387a926ee166814611acecb960207fe2f3c4fd3e (opens in a new tab)
- git.kernel.org/stable/c/373152c94e57e9592b68c100e224fbd943cfd608 (opens in a new tab)
- git.kernel.org/stable/c/387a926ee166814611acecb960207fe2f3c4fd3e (opens in a new tab)
- git.kernel.org/stable/c/416259cb5bffecaaae5f76539deb535a8c1b2c34 (opens in a new tab)
- git.kernel.org/stable/c/724d0caffd4204b46f78efe22f18f8338031c6e1 (opens in a new tab)
- git.kernel.org/stable/c/9a0dc9279d0907b198f205a693aedf696b08145d (opens in a new tab)
- git.kernel.org/stable/c/ae847ab29ded2d7cece4d5970f0edefa4137bf2f (opens in a new tab)
- git.kernel.org/stable/c/d366a01475f927402c96a3fe78bfc06b924fc87d (opens in a new tab)
- git.kernel.org/stable/c/d5b57bb314d79e99bebb58a53588fa11dd4dbf69 (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-8781-1 (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)