CVE-2026-93787

HIGHPre-NVD 8.18.1—
EchelonGraph scoreHIGH confidence

Score 8.1 from GitHub Security Advisory (severity: HIGH) published 2026-09-24. A secondary CVSS source baseline 8.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
8.1EG
EchelonGraph verdictPlan mitigationSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 8.1Exploit: 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: bound dirent name against end of SMB response in cifs_filldir

cifs_filldir() copies the entry name out of an SMB1 TRANS2_FIND_FIRST / FIND_NEXT response using a length (de.namelen) supplied by the server. The kmalloc'd SMB response buffer is bounded, but nothing checks that de.name + de.namelen still lies inside that buffer before the eventual filldir64() -> verify_dirent_name() -> memchr() reads namelen bytes.

A hostile SMB1 server that returns an oversized FileNameLength in a directory entry therefore causes memchr() to read past the end of the response slab buffer. Reachable from any user who can list a directory on a CIFS mount served by an attacker-controlled server (getdents64() on the mounted directory):

BUG: KASAN: slab-out-of-bounds in memchr+0x71/0x80 Read of size 1 at addr ffff88800e0640cc by task poc/115 Call Trace: dump_stack_lvl+0x64/0x80 print_report+0xce/0x620 kasan_report+0xec/0x120 memchr+0x71/0x80 filldir64+0x4c/0x6a0 cifs_filldir.constprop.0+0x9bb/0x1e00 cifs_readdir+0x2101/0x3380 iterate_dir+0x19c/0x520 __x64_sys_getdents64+0x126/0x210 do_syscall_64+0x107/0x5a0 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Pass the end-of-response pointer down to cifs_filldir() and reject entries whose name would extend past that boundary.

This bug was discovered by Artiphishell's vTriage pipeline, which generated a userspace reproducer (an emulated hostile SMB1 server plus a getdents64() client) that reliably triggers the KASAN report on an unpatched kernel. The fix below was drafted with the Claude coding assistant; a userspace reproducer is available on request.

CVSS v3
8.1
EG Score
8.1HIGHhigh confidence
EG Risk
41
EG Risk 41/100CISA 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
Severity81% × 45%
Exploitation0% × 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
0.3%
EPSS %ILE
25th
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 24, 2026

Last Modified

October 3, 2026

Advisory Details (3)

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

smb: client: bound dirent name against end of SMB response in cifs_filldir - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/f8cf09a53a0dc1da298e9dd0ba5f21710cf119d6
generic

smb: client: bound dirent name against end of SMB response in cifs_filldir - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/6e3b965267b7313903baba2739992b1e2e92d540
generic

smb: client: bound dirent name against end of SMB response in cifs_filldir - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/03003506c86f90312b0966283662c42fcab66e4b

Vendor Advisories for CVE-2026-93787(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 (179 versions)
  • every version up to 7.2.6-1: fixed in 7.2.6-1
—

Data Freshness Timeline

(refreshed 44× in last 7d / 66× 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 08:26 UTCEG score recompute
  2. 2026-10-05 08:26 UTCVendor advisory
  3. 2026-10-05 08:26 UTCGHSA enrichment
  4. 2026-10-04 23:23 UTCEPSS rescore
  5. 2026-10-04 21:13 UTCVendor advisory
  6. 2026-10-04 21:13 UTCGHSA enrichment
  7. 2026-10-04 09:59 UTCVendor advisory
  8. 2026-10-04 09:59 UTCGHSA enrichment
  9. 2026-10-03 22:46 UTCEG score recompute
  10. 2026-10-03 22:46 UTCVendor advisory
  11. 2026-10-03 22:46 UTCGHSA enrichment
  12. 2026-10-03 14:26 UTCEPSS rescore
  13. 2026-10-03 11:33 UTCVendor advisory
  14. 2026-10-03 11:33 UTCGHSA enrichment
  15. 2026-10-03 01:23 UTCEG score recompute
  16. 2026-10-03 01:23 UTCVendor advisory
  17. 2026-10-03 01:23 UTCGHSA enrichment
  18. 2026-10-02 14:06 UTCVendor advisory
  19. 2026-10-02 14:05 UTCGHSA enrichment
  20. 2026-10-02 02:52 UTCEG score recompute
  21. 2026-10-02 02:52 UTCVendor advisory
  22. 2026-10-02 02:51 UTCGHSA enrichment
  23. 2026-10-01 19:51 UTCEPSS rescore
  24. 2026-10-01 15:25 UTCVendor advisory
  25. 2026-10-01 15:25 UTCGHSA enrichment
Show 41 more
  1. 2026-10-01 04:13 UTCVendor advisory
  2. 2026-10-01 04:13 UTCGHSA enrichment
  3. 2026-09-30 17:00 UTCEG score recompute
  4. 2026-09-30 17:00 UTCVendor advisory
  5. 2026-09-30 17:00 UTCGHSA enrichment
  6. 2026-09-30 15:04 UTCEPSS rescore
  7. 2026-09-30 05:48 UTCVendor advisory
  8. 2026-09-30 05:48 UTCGHSA enrichment
  9. 2026-09-29 18:34 UTCEG score recompute
  10. 2026-09-29 18:34 UTCVendor advisory
  11. 2026-09-29 18:33 UTCGHSA enrichment
  12. 2026-09-29 07:20 UTCEG score recompute
  13. 2026-09-29 07:20 UTCVendor advisory
  14. 2026-09-29 07:20 UTCGHSA enrichment
  15. 2026-09-28 20:08 UTCEG score recompute
  16. 2026-09-28 20:08 UTCVendor advisory
  17. 2026-09-28 20:07 UTCGHSA enrichment
  18. 2026-09-28 13:52 UTCEPSS rescore
  19. 2026-09-28 13:52 UTCEPSS rescore
  20. 2026-09-28 08:52 UTCVendor advisory
  21. 2026-09-28 08:52 UTCGHSA enrichment
  22. 2026-09-27 21:40 UTCEG score recompute
  23. 2026-09-27 21:40 UTCGHSA enrichment
  24. 2026-09-27 13:49 UTCEPSS rescore
  25. 2026-09-27 10:27 UTCGHSA enrichment
  26. 2026-09-26 23:13 UTCEG score recompute
  27. 2026-09-26 23:12 UTCGHSA enrichment
  28. 2026-09-26 15:59 UTCEPSS rescore
  29. 2026-09-26 11:56 UTCGHSA enrichment
  30. 2026-09-26 00:44 UTCEG score recompute
  31. 2026-09-26 00:44 UTCGHSA enrichment
  32. 2026-09-25 13:24 UTCEG score recompute
  33. 2026-09-25 13:23 UTCGHSA enrichment
  34. 2026-09-25 12:57 UTCEG score recompute
  35. 2026-09-25 12:57 UTCGHSA enrichment
  36. 2026-09-25 05:18 UTCEG score recompute▲ 8.10
  37. 2026-09-25 05:18 UTCGHSA enrichment
  38. 2026-09-25 05:16 UTCMITRE cvelistV5CVSS v3 → 8.1 · severity → HIGH
  39. 2026-09-24 17:33 UTCNVD update
  40. 2026-09-24 16:30 UTCEG score recompute
  41. 2026-09-24 16:26 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-93787?
CVE-2026-93787 is a high vulnerability published on September 24, 2026. In the Linux kernel, the following vulnerability has been resolved: smb: client: bound dirent name against end of SMB response in cifs_filldir cifsfilldir() copies the entry name out of an SMB1 TRANS2FIND_FIRST / FIND_NEXT response using a length (de.namelen) supplied by the server. The kmalloc'd…
When was CVE-2026-93787 disclosed?
CVE-2026-93787 was first published on September 24, 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-2026-93787 actively exploited?
CVE-2026-93787 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (25th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-93787?
CVE-2026-93787 has a CVSS base score of 8.1 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-93787?
No fix for CVE-2026-93787 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-2026-93787 are linked in the Vendor Advisories panel on this page.

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