CVE-2026-63817

HIGHPre-NVD 7.87.8—
EchelonGraph scoreHIGH confidence

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2026-07-19. a secondary CVSS source baseline 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
7.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.8Exploit: 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:

f2fs: validate compress cache inode only when enabled

F2FS_COMPRESS_INO() uses NM_I(sbi)->max_nid as the synthetic inode number for the compressed page cache inode. That inode only exists when the compress_cache mount option is enabled.

When compress_cache is disabled, max_nid is outside the valid inode range. A corrupted directory entry that points to ino == max_nid should therefore be rejected by f2fs_check_nid_range(). However, is_meta_ino() currently treats F2FS_COMPRESS_INO() as a meta inode unconditionally, so f2fs_iget() bypasses do_read_inode() and its nid range check, and instantiates a fake internal inode instead.

Gate the compressed cache inode case on COMPRESS_CACHE, matching f2fs_init_compress_inode(). With compress_cache disabled, ino == max_nid now follows the normal inode path and is rejected as an out-of-range nid.

CVSS v3
7.8
EG Score
7.8(high)
EG Risk
40(Track)
EG Risk 40/100SSVC: Track

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. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity78% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
3%
KEV
Not listed

Published

July 19, 2026

Last Modified

July 24, 2026

Advisory Details (6)

Auto-updated Jul 21, 2026
No patch confirmed yet.
generic

f2fs: validate compress cache inode only when enabled - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/77f216ff9ce5cde8eed9f6d12707e906dffdc9f7
generic

f2fs: validate compress cache inode only when enabled - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/5073c66a96a9c23c0c2533ed4ed06e42f9021208
generic

f2fs: validate compress cache inode only when enabled - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/29115b8c9172d34e67ab26cc4f6c209b7a236d7a
generic

f2fs: validate compress cache inode only when enabled - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/16161444c30d8dff9428abbae42b72ce4e32a932
generic

f2fs: validate compress cache inode only when enabled - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/13e4b59d3a9413f66f116fa6c4828519b960a5ea
generic

f2fs: validate compress cache inode only when enabled - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/0969926d987bbde9a1aa49da317582ba37095805

Vendor Advisories for CVE-2026-63817(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 22× in last 7d / 29× 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. 2026-07-27 06:08 UTCGHSA enrichment
  2. 2026-07-26 17:19 UTCEG score recompute
  3. 2026-07-26 17:19 UTCGHSA enrichment
  4. 2026-07-26 14:54 UTCEPSS rescore
  5. 2026-07-26 14:54 UTCEPSS rescore
  6. 2026-07-26 04:31 UTCEG score recompute
  7. 2026-07-26 04:31 UTCGHSA enrichment
  8. 2026-07-24 14:18 UTCEPSS rescore
  9. 2026-07-24 14:18 UTCEPSS rescore
  10. 2026-07-23 14:18 UTCEPSS rescore
  11. 2026-07-23 14:18 UTCEPSS rescore
  12. 2026-07-23 03:22 UTCEG score recompute
  13. 2026-07-22 14:08 UTCEPSS rescore
  14. 2026-07-22 14:08 UTCEPSS rescore
  15. 2026-07-21 15:25 UTCEPSS rescore
  16. 2026-07-21 15:25 UTCEPSS rescore
  17. 2026-07-20 17:45 UTCEG score recompute
  18. 2026-07-20 17:45 UTCGHSA enrichment
  19. 2026-07-20 17:08 UTCEPSS rescore
  20. 2026-07-20 14:44 UTCEG score recompute▲ 7.80
  21. 2026-07-20 14:43 UTCGHSA enrichment
  22. 2026-07-20 14:32 UTCMITRE cvelistV5CVSS v3 → 7.8 · severity → HIGH
  23. 2026-07-19 15:26 UTCGHSA enrichment
  24. 2026-07-19 15:15 UTCGHSA enrichment
  25. 2026-07-19 15:15 UTCGHSA enrichment
Show 4 more
  1. 2026-07-19 13:00 UTCGHSA enrichment
  2. 2026-07-19 12:26 UTCNVD update
  3. 2026-07-19 12:13 UTCEG score recompute
  4. 2026-07-19 12:10 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-63817?
CVE-2026-63817 is a high vulnerability published on July 19, 2026. In the Linux kernel, the following vulnerability has been resolved: f2fs: validate compress cache inode only when enabled F2FSCOMPRESSINO() uses NMI(sbi)->maxnid as the synthetic inode number for the compressed page cache inode. That inode only exists when the compress_cache mount option is…
When was CVE-2026-63817 disclosed?
CVE-2026-63817 was first published in the National Vulnerability Database on July 19, 2026, with the most recent update on July 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-63817 actively exploited?
CVE-2026-63817 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 97.3% of all scored CVEs.
What is the CVSS score of CVE-2026-63817?
CVE-2026-63817 has a CVSS v3 base score of 7.8 (NVD).
How do I remediate CVE-2026-63817?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-63817, 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.

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