CVE-2026-67191

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-07-29. the CNA's CVSS baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:vulncheck, epss, ghsa
Trending — 3 sources updated this week
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.8Exploit: None knownExposed: 0

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

Xlight FTP Server before 3.9.5 contains a pre-authentication heap buffer overflow vulnerability that allows remote unauthenticated attackers to write past the end of a heap buffer by sending a malformed SSH client identification string. A logic error in the recv loop's termination condition uses an incorrect OR operator where an AND operator is required, enabling exploitation on any SSH or SFTP connection before authentication occurs.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
44(Track)
EG Risk 44/100SSVC: 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
Severity98% × 45%
Exploitation1% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
48%
KEV
Not listed

Published

July 29, 2026

Last Modified

August 14, 2026

Advisory Details (2)

Auto-updated Sep 18, 2026
No patch confirmed yet.
generic

Xlight FTP Server < 3.9.5 Pre-Auth Heap Buffer Overflow via SSH Parser | Advisories | VulnCheck

https://www.vulncheck.com/advisories/xlight-ftp-server-pre-auth-heap-buffer-overflow-via-ssh-parser
generic

Xlight FTP Server - what is new

https://www.xlightftpd.com/whatsnew.htm

Vendor Advisories for CVE-2026-67191(1)

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

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 28× in last 7d / 142× 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.

Showing the most recent 100 of 329 total refreshes for this CVE.

  1. 2026-09-20 20:16 UTCEPSS rescore
  2. 2026-09-20 11:16 UTCGHSA enrichment
  3. 2026-09-20 04:32 UTCGHSA enrichment
  4. 2026-09-20 00:23 UTCEG score recompute
  5. 2026-09-20 00:23 UTCGHSA enrichment
  6. 2026-09-19 04:53 UTCGHSA enrichment
  7. 2026-09-19 00:05 UTCGHSA enrichment
  8. 2026-09-18 19:34 UTCEG score recompute
  9. 2026-09-18 19:34 UTCGHSA enrichment
  10. 2026-09-18 19:28 UTCEPSS rescore
  11. 2026-09-18 15:17 UTCGHSA enrichment
  12. 2026-09-18 09:59 UTCGHSA enrichment
  13. 2026-09-18 05:50 UTCGHSA enrichment
  14. 2026-09-18 01:40 UTCEG score recompute
  15. 2026-09-18 01:40 UTCGHSA enrichment
  16. 2026-09-17 10:24 UTCGHSA enrichment
  17. 2026-09-17 06:13 UTCGHSA enrichment
  18. 2026-09-17 01:35 UTCEG score recompute
  19. 2026-09-17 01:35 UTCGHSA enrichment
  20. 2026-09-16 14:08 UTCEPSS rescore
  21. 2026-09-16 11:48 UTCGHSA enrichment
  22. 2026-09-16 05:48 UTCEG score recompute
  23. 2026-09-16 05:48 UTCGHSA enrichment
  24. 2026-09-16 05:15 UTCEPSS rescore
  25. 2026-09-15 07:54 UTCEG score recompute
Show 75 more
  1. 2026-09-15 07:54 UTCGHSA enrichment
  2. 2026-09-14 15:04 UTCGHSA enrichment
  3. 2026-09-14 10:50 UTCGHSA enrichment
  4. 2026-09-14 06:41 UTCGHSA enrichment
  5. 2026-09-14 02:32 UTCGHSA enrichment
  6. 2026-09-13 22:23 UTCGHSA enrichment
  7. 2026-09-13 18:14 UTCEG score recompute
  8. 2026-09-13 18:14 UTCGHSA enrichment
  9. 2026-09-13 14:05 UTCGHSA enrichment
  10. 2026-09-13 09:55 UTCGHSA enrichment
  11. 2026-09-13 05:45 UTCGHSA enrichment
  12. 2026-09-13 01:36 UTCGHSA enrichment
  13. 2026-09-12 21:27 UTCGHSA enrichment
  14. 2026-09-12 17:17 UTCEG score recompute
  15. 2026-09-12 17:17 UTCGHSA enrichment
  16. 2026-09-12 13:08 UTCGHSA enrichment
  17. 2026-09-12 08:58 UTCGHSA enrichment
  18. 2026-09-12 04:48 UTCGHSA enrichment
  19. 2026-09-12 00:38 UTCGHSA enrichment
  20. 2026-09-11 19:22 UTCGHSA enrichment
  21. 2026-09-11 15:06 UTCEG score recompute
  22. 2026-09-11 15:06 UTCGHSA enrichment
  23. 2026-09-11 14:53 UTCEPSS rescore
  24. 2026-09-11 09:37 UTCEPSS rescore
  25. 2026-09-11 06:29 UTCGHSA enrichment
  26. 2026-09-11 01:24 UTCGHSA enrichment
  27. 2026-09-10 19:51 UTCGHSA enrichment
  28. 2026-09-10 14:33 UTCGHSA enrichment
  29. 2026-09-10 10:11 UTCEG score recompute
  30. 2026-09-10 10:11 UTCGHSA enrichment
  31. 2026-09-10 04:33 UTCGHSA enrichment
  32. 2026-09-09 11:56 UTCGHSA enrichment
  33. 2026-09-09 07:47 UTCEG score recompute
  34. 2026-09-09 07:47 UTCGHSA enrichment
  35. 2026-09-08 22:01 UTCEPSS rescore
  36. 2026-09-08 00:57 UTCGHSA enrichment
  37. 2026-09-07 20:47 UTCEG score recompute
  38. 2026-09-07 20:47 UTCGHSA enrichment
  39. 2026-09-07 16:01 UTCEPSS rescore
  40. 2026-09-06 22:41 UTCGHSA enrichment
  41. 2026-09-06 15:57 UTCEG score recompute
  42. 2026-09-06 15:56 UTCGHSA enrichment
  43. 2026-09-06 13:47 UTCEPSS rescore
  44. 2026-09-06 11:46 UTCGHSA enrichment
  45. 2026-09-06 07:36 UTCGHSA enrichment
  46. 2026-09-06 03:26 UTCGHSA enrichment
  47. 2026-09-05 23:16 UTCGHSA enrichment
  48. 2026-09-05 19:06 UTCEG score recompute
  49. 2026-09-05 19:06 UTCGHSA enrichment
  50. 2026-09-05 15:31 UTCEPSS rescore
  51. 2026-09-05 09:21 UTCGHSA enrichment
  52. 2026-09-05 05:11 UTCGHSA enrichment
  53. 2026-09-04 16:17 UTCEG score recompute
  54. 2026-09-04 16:17 UTCGHSA enrichment
  55. 2026-09-04 11:55 UTCEG score recompute
  56. 2026-09-04 11:55 UTCGHSA enrichment
  57. 2026-09-04 05:07 UTCEPSS rescore
  58. 2026-09-02 14:12 UTCEPSS rescore
  59. 2026-09-01 22:46 UTCEG score recompute
  60. 2026-09-01 22:46 UTCGHSA enrichment
  61. 2026-09-01 13:54 UTCEPSS rescore
  62. 2026-09-01 04:40 UTCEPSS rescore
  63. 2026-08-31 23:56 UTCGHSA enrichment
  64. 2026-08-31 04:25 UTCGHSA enrichment
  65. 2026-08-31 00:15 UTCGHSA enrichment
  66. 2026-08-30 20:06 UTCEG score recompute
  67. 2026-08-30 20:06 UTCGHSA enrichment
  68. 2026-08-30 19:17 UTCEPSS rescore
  69. 2026-08-30 15:55 UTCGHSA enrichment
  70. 2026-08-30 11:45 UTCGHSA enrichment
  71. 2026-08-30 07:36 UTCGHSA enrichment
  72. 2026-08-30 03:27 UTCEG score recompute
  73. 2026-08-30 03:27 UTCGHSA enrichment
  74. 2026-08-30 01:22 UTCEPSS rescore
  75. 2026-08-29 23:17 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-67191?
CVE-2026-67191 is a critical vulnerability published on July 29, 2026. Xlight FTP Server before 3.9.5 contains a pre-authentication heap buffer overflow vulnerability that allows remote unauthenticated attackers to write past the end of a heap buffer by sending a malformed SSH client identification string. A logic error in the recv loop's termination condition uses an…
When was CVE-2026-67191 disclosed?
CVE-2026-67191 was first published in the National Vulnerability Database on July 29, 2026, with the most recent update on August 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-67191 actively exploited?
CVE-2026-67191 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 51.8% of all scored CVEs.
What is the CVSS score of CVE-2026-67191?
CVE-2026-67191 has a CVSS v4.0 base score of 9.8 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-67191?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-67191, 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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