Security Digest · Vulnerability record
CVE-2026-80521: af_unix: Unlink scc_entry in unix_del_edge().
In the Linux kernel, the following vulnerability has been resolved: afunix: Unlink sccentry in unixdeledge().
CVSS 7.8 High EPSS 0.2% · p6 Patch this week
Should you act?
Normal patch cycle
No exploitation signal; fix it in your next routine update if you are affected. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- No confirmed exploitation. It is not in CISA’s KEV catalog. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.2%, percentile 6: FIRST’s model estimates a 0.2% chance of exploitation activity in the next 30 days, higher than 6% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Needs local access needed. Lower urgency for most teams unless an attacker could already run code on the machine.
- Editorial verdict: Patch this week. Linux AF_UNIX CVE-2026-80521: Public Container Escape — If you run untrusted or third-party code in containers on a 6.10+ kernel, install fixed kernels as they ship and move that code behind stronger isolation now; a public exploit turns an unprivileged container process into a host compromise.
What it is
In the Linux kernel, the following vulnerability has been resolved: afunix: Unlink sccentry in unixdeledge(). Kyle Zeng reported that GC could free a dead SCC partially. The scenario is as follows: 1) Create two SCCs: X -. A B ^--' 2) Run the following concurrently: 2-1) send() sk-B to sk-B from sk-X 2-2) close() both A and B At 2-1), there is a small window where unixaddedges() publishes a new edge (B B) to GC but its skb is not queued by skbqueuetail(). If 2-2) completes before skbqueuetail() and GC is triggered, it judges A B as dead, but B is not freed because GC cannot collect the not-yet-queued skb holding the B B edge. X -. A B -. This edge is visible ^--' ^..' but skb is not This itself is not a problem since the next GC run will judge B as dead as well and free it finally. X -. A B -. ^--' ^--' However, X's SCC forces the next GC to call unixwalksccfast(), and it iterates over A through B's sccentry. Let's unlink sccentry before freeing the vertex in unixdeledge().
Product: Linux Linux · Assigned by: Linux · Published: 2026-08-26
Affected and fixed versions
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| Linux | Linux | 5dfd283f4651d04dbb70ceb9ae5c4a30eda3c52a < 2b6c2842692d08e7acaf32d1eb47f95def35f3fe, de7921631ff323369aa63a4324695ab54ea4047e < 6fda5c51b8e43a8440f76e65c89d9f95ddb2ef33, 4090fa373f0e763c43610853d2774b5979915959 < 1293fd69a50d188a5788b08ba3741a3e86be1608, 4090fa373f0e763c43610853d2774b5979915959 <… |
| Linux | Linux | 6.10 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| Linux | 3.1 | 7.8 High | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
- Attack vector: local access needed
- Attack complexity: low
- Privileges required: low (any account)
- User interaction: none
- Scope: unchanged
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- FIRST EPSS (model of 2026-10-21): 0.17% probability of exploitation activity in the next 30 days; percentile 6.
Timeline
- — CVE record published by Linux
- — erroneo.us brief: Linux AF_UNIX CVE-2026-80521: Public Container Escape
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- CVE.org record CVE-2026-80521 cve.org
- NVD entry CVE-2026-80521 nvd.nist.gov
Other references from the CVE record and advisory
- git.kernel.org git.kernel.org
- git.kernel.org git.kernel.org
- git.kernel.org git.kernel.org
- git.kernel.org git.kernel.org
- git.kernel.org git.kernel.org
- git.kernel.org git.kernel.org