CVE-2026-63804

UNRATEDCVSS · not yet scoredTrending — 3 sources updated this week
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EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • No CVSS published and no exploitation signals yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS v2: —Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
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EG Score
0.0(none)
EG Risk
0
EG Risk 0/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses intrinsic severity with real-world exploitation and automatability, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. It is distinct from the 0–10 EG Score, which measures severity.

EPSS PROB
0%
EPSS %ILE
6%
KEV
Not listed

Published

July 19, 2026

Last Modified

July 19, 2026

References (5)

Vendor Advisories for CVE-2026-63804(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Data Freshness Timeline

(refreshed 18× in last 7d / 21× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-26 14:54 UTCEPSS rescore
  2. 2026-07-26 14:54 UTCEPSS rescore
  3. 2026-07-26 11:10 UTCEG score recompute
  4. 2026-07-26 11:09 UTCGHSA enrichment
  5. 2026-07-25 14:18 UTCEPSS rescore
  6. 2026-07-25 14:18 UTCEPSS rescore
  7. 2026-07-24 14:18 UTCEPSS rescore
  8. 2026-07-24 14:18 UTCEPSS rescore
  9. 2026-07-23 14:18 UTCEPSS rescore
  10. 2026-07-23 14:18 UTCEPSS rescore
  11. 2026-07-23 03:22 UTCEG score recompute
  12. 2026-07-22 14:08 UTCEPSS rescore
  13. 2026-07-22 14:08 UTCEPSS rescore
  14. 2026-07-21 15:25 UTCEPSS rescore
  15. 2026-07-21 15:25 UTCEPSS rescore
  16. 2026-07-20 17:46 UTCEG score recompute
  17. 2026-07-20 17:46 UTCGHSA enrichment
  18. 2026-07-20 17:08 UTCEPSS rescore
  19. 2026-07-19 12:26 UTCNVD update
  20. 2026-07-19 12:14 UTCEG score recompute
  21. 2026-07-19 12:10 UTCMITRE cvelistV5first tracked

Frequently asked(4)

What is CVE-2026-63804?
CVE-2026-63804 is a publicly disclosed vulnerability published on July 19, 2026. In the Linux kernel, the following vulnerability has been resolved: gfs2: fix use-after-free in gfs2qddealloc gfs2qddealloc(), called as an RCU callback from gfs2qddispose(), accesses the superblock object sdp through qd->qd_sbd after freeing qd. It does so to decrement sdquotacount and wake up…
When was CVE-2026-63804 disclosed?
CVE-2026-63804 was first published in the National Vulnerability Database on July 19, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-63804 actively exploited?
CVE-2026-63804 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 93.6% of all scored CVEs.
How do I remediate CVE-2026-63804?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-63804, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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