Do Son 
TL;DR
Researchers published full details and proof-of-concept exploit code for CVE-2026-53361, a use-after-free in the Linux kernel AF_UNIX garbage collector. The flaw allows an unprivileged local user to escape a container and corrupt kernel memory. Multiple stable and enterprise kernels are affected, and patches are now available.
- CVE: CVE-2026-53361
- CVSS: 7.1 (High · CVSSv3)
- Product: Linux
- Affected: ceb8bd6c69c1680fd9b45e7f16d7170c9c7513a5, 328840c93bd6a4871dd10908d01b41eab83eb8e2, 8b90a9f819dc2a06baae4ec1a64d875e53b824ec, 6.1.141, 6.6.93, 6.9
- Impact: af_unix: Set gc_in_progress to true in unix_gc().
- Status: No confirmed exploitation yet
- Patched in: 20aa894d475bd8086b25c1113ec4ca70f70c7a98, 82c17e13d404f686e164590483fd6c1abaa675d0, 591f1ac217428a6d2b32a8ac14aac0fab44f155a, 0cfa78c050662784fc8e3ab26dbfd1dc632b2082 (+6 more)
- EPSS: 0.1% (30-day)
- Action: Update to 20aa894d475bd8086b25c1113ec4ca70f70c7a98, 82c17e13d404f686e164590483fd6c1abaa675d0, 591f1ac217428a6d2b32a8ac14aac0fab44f155a, 0cfa78c050662784fc8e3ab26dbfd1dc632b2082 (+6 more) now
Why It Matters
This CVE-2026-53361 container escape bug needs no special privileges. Any local user with a shell can trigger it. Therefore shared and multi-tenant hosts face the highest risk.
The AF_UNIX garbage collector runs in almost every Linux configuration. As a result, the attack surface is broad. A public proof-of-concept from researcher sgkdev raises the urgency further.
How the Attack Works
The AF_UNIX garbage collector reclaims “in-flight” sockets that form unreachable reference cycles. Meanwhile, a concurrent MSG_PEEK on an in-flight file descriptor takes a reference the collector never counts.
Because of that miscount, the collector can free a socket that is still alive. This leaves a dangling sk_buff behind. The peek should back off during collection, yet the gc_in_progress flag can read false mid-run.
Consequently, the peek slips through and the race opens. SentinelOne notes the same desynchronization can corrupt kernel structures such as unix_sock and scm_fp_list. The single-vector proof-of-concept uses the MSG_PEEK path alone.
Affected Versions
The published exploit targets several current kernels. Specifically, it covers stable 6.12 up to 6.12.94, Ubuntu 24.04 HWE 6.17 up to 6.17.0-41, RHEL 10 on 6.12, and Debian trixie up to 6.12.94+deb13.
The 7.x kernels and the Ubuntu 6.8 GA kernel remain vulnerable but fall outside this exploit’s scope. Kernel maintainer Kuniyuki Iwashima authored the upstream fix.
Patch and Mitigation Steps
First, update to a patched kernel and reboot. The fix sets gc_in_progress inside unix_gc(), landing in stable commit d82ba05263c6 and its backports. Stable 6.12.95, for example, carries the fix.
Next, restrict local access on shared hosts until you patch. You should also enforce least privilege on services that pass file descriptors over Unix sockets. No supported runtime workaround exists, so patching stays essential.
The full technical writeup and proof-of-concept exploit code appear in the researcher’s bad_garbage repository. Administrators should confirm their kernel build against vendor advisories today.
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