SEPTEMBER 18, 2026
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Case File

CVE-2026-80521

HIGH · CVSS 7.8 EPSS 0.12%

Source: NVD + CISA KEV + EPSS · Published 2026-08-26 · Last synced 2026-09-18

CyberRota Analysis

AI-Generated

The vulnerability affects the Linux kernel's handling of socket connections, specifically in the management of strongly connected components (SCCs) during garbage collection. An attacker could exploit a race condition between sending data and closing sockets, potentially leading to a denial of service due to improper resource management. System administrators and developers working with Linux kernel networking should prioritize this issue to ensure system stability and prevent potential service disruptions.

CVE
CVE-2026-80521
Severity
HIGH
CVSS
7.8
EPSS
0.12%
Linux

Original NVD Description

In the Linux kernel, the following vulnerability has been resolved: af_unix: Unlink scc_entry in unix_del_edge(). 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 unix_add_edges() publishes a new edge (B <-> B) to GC but its skb is not queued by skb_queue_tail(). If 2-2) completes before skb_queue_tail() 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 unix_walk_scc_fast(), and it iterates over A through B's scc_entry. Let's unlink scc_entry before freeing the vertex in unix_del_edge().