Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
AV AC PR UI S C I A CVSS EPSS %ile KEV L L L N U H H H 7.8 .0014 3.6 —
AFFECTED Product Versions Fixed Linux a475c5dd16e57c570113eccba51955b5df8bb052 – — Linux 6.6 – 6.6.144
TIMELINE Jul 19 Reserved by Linux Jul 19 Published (CNA: Linux) Aug 17 ENRICHED — CVE-2026-63804 (Linux). Received CVSS 7.8 and CPE data from NVD.
In the Linux kernel, the following vulnerability has been resolved: gfs2: fix use-after-free in gfs2_qd_dealloc gfs2_qd_dealloc(), called as an RCU callback from gfs2_qd_dispose(), accesses the superblock object sdp through qd->qd_sbd after freeing qd. It does so to decrement sd_quota_count and wake up sd_kill_wait. However, by the time the RCU callback runs, gfs2_put_super() may have already freed sdp via free_sbd(). This can happen when gfs2_quota_cleanup() is called during unmount: it disposes of quota objects via call_rcu() and then waits on sd_kill_wait with a 60-second timeout. If the timeout expires, or if gfs2_gl_hash_clear() triggers additional qd_put() calls that schedule more RCU callbacks after the wait completes, gfs2_put_super() will proceed to free the superblock while RCU callbacks referencing it are still pending. Add an rcu_barrier() before free_sbd() in gfs2_put_super() to ensure all pending RCU callbacks (including gfs2_qd_dealloc) have completed before the superblock is freed.
| Date | Event | Detail |
|---|---|---|
| July 19, 2026 | Reserved | Reserved by Linux |
| July 19, 2026 | Published | Published (CNA: Linux) |
| August 17, 2026 | ENRICHED | ENRICHED — CVE-2026-63804 (Linux). Received CVSS 7.8 and CPE data from NVD. |
Authoritative record: CVE-2026-63804 at cve.org
Vendors: linux
Weaknesses: CWE-416
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-63804 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.