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Vulnerabilities
Vulnerability

CVE-2026-46086

Reference data from vuln.mlab.sh, coverage from our own index.

CVSS
5.5 Medium
Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Risk score
44.0
Published
2026-05-27
Status
Published

In the Linux kernel, the following vulnerability has been resolved: net: bridge: use a stable FDB dst snapshot in RCU readers Local FDB entries can be rewritten in place by `fdb_delete_local()`, which updates `f->dst` to another port or to `NULL` while keeping the entry alive. Several bridge RCU readers inspect `f->dst`, including `br_fdb_fillbuf()` through the `brforward_read()` sysfs path. These readers currently load `f->dst` multiple times and can therefore observe inconsistent values across the check and later dereference. In `br_fdb_fillbuf()`, this means a concurrent local-FDB update can change `f->dst` after the NULL check and before the `port_no` dereference, leading to a NULL-ptr-deref. Fix this by taking a single `READ_ONCE()` snapshot of `f->dst` in each affected RCU reader and using that snapshot for the rest of the access sequence. Also publish the in-place `f->dst` updates in `fdb_delete_local()` with `WRITE_ONCE()` so the readers and writer use matching access patterns. A flaw was found in the Linux kernel. Inconsistent handling of local Forwarding Database (FDB) entries in the bridge networking component's RCU (Read-Copy-Update) readers can lead to a null-pointer dereference. A local attacker could exploit this by triggering a concurrent update to an FDB entry, causing the system to crash and resulting in a Denial of Service (DoS).

Weaknesses

CWE-367

Coverage 8

Advisories and references