CVE-2026-97557

HIGHPre-NVD 7.57.5—
EchelonGraph scoreHIGH confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-09-25. A secondary CVSS source baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
7.5EG
EchelonGraph verdictPlan mitigationSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.7%CVSS: 7.5Exploit: None knownExposed services: Not assessed

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

In the Linux kernel, the following vulnerability has been resolved:

smb: client: avoid leaking refcount in cifs_queue_oplock_break()

cifs_queue_oplock_break() unconditionally takes a reference on the target file before queueing cifs_oplock_break(). Only that work item decreases the reference counter again.

If another oplock break arrives while that work is still queued, queue_work() will return false and not queue this second work item. As a result, we will never reach the point to drop the file reference again and are leaking this reference. This can be triggered when interacting with a slow-responding server.

As a result, later unmount operations for this file system will fail with

BUG: Dentry ... still in use (1) [unmount of cifs cifs] VFS: Busy inodes after unmount of cifs (cifs) kernel BUG at fs/super.c:777!

Fix this by only incrementing the reference count if the work has been queued successfully. Taking it after queue_work() is safe because all three callers hold tcon->open_file_lock across the call and _cifsFileInfo_put() decrements under that same lock, so a worker that starts the handler in the window cannot drop the reference before it has been taken.

CVSS v3
7.5
EG Score
7.5HIGHhigh confidence
EG Risk
39
EG Risk 39/100CISA SSVC

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
Severity75% × 45%
Exploitation1% × 40%
Automatability30% × 15%
CISA SSVC: Track at low or medium mission impact; Track or Attend at high (mission-essential systems).
Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.
EPSS PROB
0.7%
EPSS %ILE
49th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track or Attend at high (mission-essential systems).

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.

Exploitation none (no KEV listing, exploit record or EPSS ≥ 50%) · Automatable unknown (not published for this CVE) · Technical impact partial (CVSS below 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

September 25, 2026

Last Modified

October 3, 2026

Advisory Details (4)

Auto-updated Sep 25, 2026
No patch confirmed yet.
generic

smb: client: avoid leaking refcount in cifs_queue_oplock_break() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/9f2e63f1b2d5fc5b5423424902c091123e220e7e
generic

smb: client: avoid leaking refcount in cifs_queue_oplock_break() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/dfe7b750c7e069873a8a57a11c816831a235618a
generic

smb: client: avoid leaking refcount in cifs_queue_oplock_break() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/2ed2c29dd9593637cfa25ac1eb23241b20202778
generic

smb: client: avoid leaking refcount in cifs_queue_oplock_break() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/af0193bbf1ac8c0f67f972998b0cc629d6116cf6

Vendor Advisories for CVE-2026-97557(2)

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

Affected Packages

(4 across 3 ecosystems)
Debian:12(2)
PackageVulnerable rangeFix by version rangeDependents
linux6.1.106-1 ... 7.2~rc7-1~exp1 (360 versions)
  • every version on: no fix on record
—
linux-6.126.12.100-1~deb12u1, 6.12.101-1~deb12u1, 6.12.107-1~deb12u1
  • every version up to 6.12.111-1~deb12u1: fixed in 6.12.111-1~deb12u1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 6.12.96-1 (35 versions)
  • every version up to 6.12.111-1: fixed in 6.12.111-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 7.2~rc7-1~exp1 (180 versions)
  • every version up to 7.2.7-1: fixed in 7.2.7-1
—

Data Freshness Timeline

(refreshed 40× in last 7d / 59× 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. 2026-10-05 02:31 UTCEG score recompute
  2. 2026-10-05 02:31 UTCVendor advisory
  3. 2026-10-05 02:31 UTCGHSA enrichment
  4. 2026-10-04 23:23 UTCEPSS rescore
  5. 2026-10-04 13:30 UTCVendor advisory
  6. 2026-10-04 13:30 UTCGHSA enrichment
  7. 2026-10-04 00:29 UTCEG score recompute
  8. 2026-10-04 00:29 UTCVendor advisory
  9. 2026-10-04 00:29 UTCGHSA enrichment
  10. 2026-10-03 14:26 UTCEPSS rescore
  11. 2026-10-03 11:29 UTCVendor advisory
  12. 2026-10-03 11:29 UTCGHSA enrichment
  13. 2026-10-03 05:58 UTCEG score recompute
  14. 2026-10-03 05:58 UTCVendor advisory
  15. 2026-10-03 05:58 UTCGHSA enrichment
  16. 2026-10-02 17:57 UTCEPSS rescore
  17. 2026-10-02 16:57 UTCVendor advisory
  18. 2026-10-02 16:57 UTCGHSA enrichment
  19. 2026-10-02 03:56 UTCEG score recompute
  20. 2026-10-02 03:56 UTCVendor advisory
  21. 2026-10-02 03:56 UTCGHSA enrichment
  22. 2026-10-01 19:51 UTCEPSS rescore
  23. 2026-10-01 14:53 UTCVendor advisory
  24. 2026-10-01 14:53 UTCGHSA enrichment
  25. 2026-10-01 01:53 UTCEG score recompute
Show 34 more
  1. 2026-10-01 01:53 UTCVendor advisory
  2. 2026-10-01 01:52 UTCGHSA enrichment
  3. 2026-09-30 15:04 UTCEPSS rescore
  4. 2026-09-30 12:51 UTCVendor advisory
  5. 2026-09-30 12:51 UTCGHSA enrichment
  6. 2026-09-29 23:50 UTCEG score recompute
  7. 2026-09-29 23:50 UTCVendor advisory
  8. 2026-09-29 23:50 UTCGHSA enrichment
  9. 2026-09-29 10:42 UTCVendor advisory
  10. 2026-09-29 10:42 UTCGHSA enrichment
  11. 2026-09-28 21:33 UTCEG score recompute
  12. 2026-09-28 21:33 UTCVendor advisory
  13. 2026-09-28 21:33 UTCGHSA enrichment
  14. 2026-09-28 13:52 UTCEPSS rescore
  15. 2026-09-28 13:52 UTCEPSS rescore
  16. 2026-09-28 08:33 UTCVendor advisory
  17. 2026-09-28 08:33 UTCGHSA enrichment
  18. 2026-09-27 19:32 UTCEG score recompute
  19. 2026-09-27 19:32 UTCGHSA enrichment
  20. 2026-09-27 13:49 UTCEPSS rescore
  21. 2026-09-27 06:32 UTCGHSA enrichment
  22. 2026-09-26 17:31 UTCEG score recompute
  23. 2026-09-26 17:31 UTCGHSA enrichment
  24. 2026-09-26 15:59 UTCEPSS rescore
  25. 2026-09-26 04:30 UTCEG score recompute
  26. 2026-09-26 04:30 UTCGHSA enrichment
  27. 2026-09-25 15:26 UTCEG score recompute
  28. 2026-09-25 15:26 UTCGHSA enrichment
  29. 2026-09-25 14:52 UTCEG score recompute▲ 7.50
  30. 2026-09-25 14:52 UTCGHSA enrichment
  31. 2026-09-25 14:49 UTCMITRE cvelistV5CVSS v3 → 7.5 · severity → HIGH
  32. 2026-09-25 11:29 UTCNVD update
  33. 2026-09-25 10:40 UTCEG score recompute
  34. 2026-09-25 10:27 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-97557?
CVE-2026-97557 is a high vulnerability published on September 25, 2026. In the Linux kernel, the following vulnerability has been resolved: smb: client: avoid leaking refcount in cifsqueueoplock_break() cifsqueueoplock_break() unconditionally takes a reference on the target file before queueing cifsoplockbreak(). Only that work item decreases the reference counter…
When was CVE-2026-97557 disclosed?
CVE-2026-97557 was first published on September 25, 2026, with the most recent update on October 3, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-97557 actively exploited?
CVE-2026-97557 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.7% probability of exploitation in the next 30 days (49th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-97557?
CVE-2026-97557 has a CVSS base score of 7.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-97557?
No fix for CVE-2026-97557 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The vendor advisories EchelonGraph has for CVE-2026-97557 are linked in the Vendor Advisories panel on this page.

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