CVE-2026-53273: Linux kernel · Use After Free
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 7.8 High · fixed in d366a01475f927402c96a3fe78bfc06b924fc87d : patch Linux kernel soon.
Data as of 26 Oct 2026, 15:59 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.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in d366a01475f927402c96a3fe78bfc06b924fc87d, d5b57bb314d79e99bebb58a53588fa11dd4dbf69, ae847ab29ded2d7cece4d5970f0edefa4137bf2f +12
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 |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in– |
Description
In the Linux kernel, the following vulnerability has been resolved: tee: optee: prevent use-after-free when the client exits before the supplicant Commit 70b0d6b0a199 ("tee: optee: Fix supplicant wait loop") made the client wait as killable so it can be interrupted during shutdown or after a supplicant crash. This changes the original lifetime expectations: the client task can now terminate while the supplicant is still processing its request. If the client exits first it removes the request from its queue and kfree()s it, while the request ID remains in supp->idr. A subsequent lookup on the supplicant path then dereferences freed memory, leading to a use-after-free. Serialise access to the request with supp->mutex: * Hold supp->mutex in optee_supp_recv() and optee_supp_send() while looking up and touching the request. * Let optee_supp_thrd_req() notice that the client has terminated and signal optee_supp_send() accordingly. With these changes the request cannot be freed while the supplicant still has a reference, eliminating the race.
References
- 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/ae847ab29ded2d7cece4d5970f0edefa4137bf2f (opens in a new tab)
- git.kernel.org/stable/c/9a0dc9279d0907b198f205a693aedf696b08145d (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)
- git.kernel.org/stable/c/373152c94e57e9592b68c100e224fbd943cfd608 (opens in a new tab)
- git.kernel.org/stable/c/387a926ee166814611acecb960207fe2f3c4fd3e (opens in a new tab)