CVE-2026-40355

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.5%, top 60% of all CVEs by exploit prediction. GitHub Security Advisory enrichment pending alignment with NVD CVSS.

Triggered by: NVD CVSS baseline
Sources: epss, ghsa, nvd
Trending — 3 sources updated this weekElevated
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 1%CVSS: 7.5Exploit: NoneExposed: 0

A fix is available — apply it.

In MIT Kerberos 5 (aka krb5) before 1.22.3, there is a NULL pointer dereference if an application calls gss_accept_sec_context() on a system with a NegoEx mechanism registered in /etc/gss/mech. An unauthenticated remote attacker can trigger this, causing the process to terminate in parse_nego_message.

CVSS v3
7.5
EG Score
7.5(medium)
EG Risk
50(Track)
EG Risk 50/100SSVC: 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
Severity75% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
40.2%
KEV
Not listed

Published

April 28, 2026

Last Modified

July 14, 2026

Advisory Details (3)

Auto-updated Jun 14, 2026
🔬 Proof of concept available. Upstream fix merged — awaiting tagged release. Sources: github_commit.
generic🟡 PoC Available

Advisory - Kerberos (krb5) Two Unauthenticated Network Vulnerabilities: CVE-2026-40355 & CVE-2026-40356 | Cem’s Blog

https://cems.fun/2026/04/27/krb5-two-unauthenticated-network-vulnerabilities.html
generic

Kerberos Security Advisories

https://web.mit.edu/kerberos/advisories/
github_commit

commit 2e75f0d9362f (krb5/krb5)

Fix landed in krb5/krb5 commit 2e75f0d9362f — awaiting tagged release

https://github.com/krb5/krb5/commit/2e75f0d9362fb979f5fc92829431a590a130929f

Vendor Advisories for CVE-2026-40355(9)

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

Patch Availability(6)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatinsights-proxy/insights-proxy-container-rhel9:17804204282026-06-02redhat
redhatrhui5/rhua-rhel9:17797982222026-05-27redhat
redhatkrb5-0:1.21.3-10.el10_22026-05-19redhat
redhatkrb5-0:1.21.1-10.el9_82026-05-19redhat
redhatkrb5-0:1.18.2-34.el8_102026-05-13redhat
redhatkrb5-main-1.22.2-7.hum12026-04-30redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 39× 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 121 total refreshes for this CVE.

  1. 2026-07-23 03:11 UTCEG score recompute▲ 1.60
  2. 2026-07-22 14:08 UTCEPSS rescore
  3. 2026-07-21 15:24 UTCEPSS rescore
  4. 2026-07-20 17:08 UTCEPSS rescore
  5. 2026-07-19 20:48 UTCOSV refresh
  6. 2026-07-19 14:31 UTCEPSS rescore
  7. 2026-07-19 02:29 UTCEPSS rescore
  8. 2026-07-18 10:04 UTCEPSS rescore
  9. 2026-07-16 17:03 UTCEPSS rescore
  10. 2026-07-15 16:57 UTCEPSS rescore
  11. 2026-07-15 16:57 UTCEPSS rescore
  12. 2026-07-15 02:00 UTCEPSS rescore
  13. 2026-07-14 13:19 UTCNVD updateCVSS v3 → 7.5 · severity → HIGH
  14. 2026-07-14 13:11 UTCMITRE cvelistV5CVSS v3 → 5.9 · severity → MEDIUM
  15. 2026-07-13 22:30 UTCEPSS rescore
  16. 2026-07-13 06:13 UTCEPSS rescore
  17. 2026-07-13 06:13 UTCEPSS rescore
  18. 2026-07-12 05:46 UTCEPSS rescore
  19. 2026-07-11 08:27 UTCEPSS rescore
  20. 2026-07-09 19:10 UTCEPSS rescore
  21. 2026-07-08 15:15 UTCEPSS rescore
  22. 2026-07-08 14:36 UTCNVD updateCVSS v3 → 7.5 · severity → HIGH
  23. 2026-07-07 13:46 UTCEPSS rescore
  24. 2026-07-06 16:27 UTCEPSS rescore
  25. 2026-07-06 16:27 UTCEPSS rescore
Show 75 more
  1. 2026-07-06 02:23 UTCEPSS rescore
  2. 2026-07-06 02:23 UTCEPSS rescore
  3. 2026-07-05 02:30 UTCEPSS rescore
  4. 2026-07-04 06:31 UTCEPSS rescore
  5. 2026-07-01 15:06 UTCEPSS rescore
  6. 2026-06-30 23:22 UTCEPSS rescore
  7. 2026-06-29 14:06 UTCEPSS rescore
  8. 2026-06-28 14:07 UTCEPSS rescore
  9. 2026-06-28 04:56 UTCEPSS rescore
  10. 2026-06-27 03:08 UTCEPSS rescore
  11. 2026-06-25 13:49 UTCEPSS rescore
  12. 2026-06-25 13:49 UTCEPSS rescore
  13. 2026-06-24 14:05 UTCEPSS rescore
  14. 2026-06-23 21:33 UTCEPSS rescore
  15. 2026-06-22 14:25 UTCEPSS rescore
  16. 2026-06-22 14:25 UTCEPSS rescore
  17. 2026-06-21 14:56 UTCEPSS rescore
  18. 2026-06-21 14:56 UTCEPSS rescore
  19. 2026-06-21 01:59 UTCEPSS rescore
  20. 2026-06-19 19:25 UTCEPSS rescore
  21. 2026-06-18 17:52 UTCEPSS rescore
  22. 2026-06-18 17:52 UTCEPSS rescore
  23. 2026-06-17 17:53 UTCEPSS rescore
  24. 2026-06-16 17:52 UTCEPSS rescore
  25. 2026-06-15 17:49 UTCEPSS rescore
  26. 2026-06-14 09:53 UTCVendor advisory
  27. 2026-06-14 09:53 UTCGHSA enrichment
  28. 2026-06-13 23:00 UTCEPSS rescore
  29. 2026-06-12 23:12 UTCEPSS rescore
  30. 2026-06-12 23:12 UTCEPSS rescore
  31. 2026-06-11 19:02 UTCVendor advisory
  32. 2026-06-11 19:02 UTCGHSA enrichment
  33. 2026-06-11 14:00 UTCEPSS rescore
  34. 2026-06-10 22:18 UTCEPSS rescore
  35. 2026-06-10 21:20 UTCVendor advisory
  36. 2026-06-10 21:20 UTCGHSA enrichment
  37. 2026-06-10 13:22 UTCEPSS rescore
  38. 2026-06-10 13:22 UTCEPSS rescore
  39. 2026-06-09 23:37 UTCVendor advisory
  40. 2026-06-09 23:37 UTCGHSA enrichment
  41. 2026-06-09 00:05 UTCVendor advisory
  42. 2026-06-09 00:05 UTCGHSA enrichment
  43. 2026-06-08 14:17 UTCEPSS rescore
  44. 2026-06-08 14:17 UTCEPSS rescore
  45. 2026-06-07 23:18 UTCVendor advisory
  46. 2026-06-07 23:18 UTCGHSA enrichment
  47. 2026-06-07 15:25 UTCEPSS rescore
  48. 2026-06-07 15:25 UTCEPSS rescore
  49. 2026-06-07 01:36 UTCVendor advisory
  50. 2026-06-07 01:36 UTCGHSA enrichment
  51. 2026-06-06 13:47 UTCEPSS rescore
  52. 2026-06-06 13:47 UTCEPSS rescore
  53. 2026-06-06 03:53 UTCVendor advisory
  54. 2026-06-06 03:53 UTCGHSA enrichment
  55. 2026-06-05 22:47 UTCEPSS rescore
  56. 2026-06-05 06:10 UTCEPSS rescore
  57. 2026-06-05 06:10 UTCEPSS rescore
  58. 2026-06-05 05:38 UTCVendor advisory
  59. 2026-06-05 05:38 UTCGHSA enrichment
  60. 2026-06-04 13:12 UTCEPSS rescore
  61. 2026-06-04 13:12 UTCEPSS rescore
  62. 2026-06-04 07:56 UTCVendor advisory
  63. 2026-06-04 07:56 UTCGHSA enrichment
  64. 2026-06-03 08:05 UTCVendor advisory
  65. 2026-06-03 08:05 UTCGHSA enrichment
  66. 2026-06-02 20:13 UTCEPSS rescore
  67. 2026-06-02 09:33 UTCVendor advisory
  68. 2026-06-02 09:33 UTCGHSA enrichment
  69. 2026-06-01 13:52 UTCEPSS rescore
  70. 2026-06-01 13:52 UTCEPSS rescore
  71. 2026-06-01 13:51 UTCEPSS rescore
  72. 2026-06-01 11:29 UTCVendor advisory
  73. 2026-06-01 11:28 UTCGHSA enrichment
  74. 2026-05-31 22:30 UTCEPSS rescore
  75. 2026-05-31 22:30 UTCEPSS rescore

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-40355?
CVE-2026-40355 is a high vulnerability published on April 28, 2026. In MIT Kerberos 5 (aka krb5) before 1.22.3, there is a NULL pointer dereference if an application calls gssacceptseccontext() on a system with a NegoEx mechanism registered in /etc/gss/mech. An unauthenticated remote attacker can trigger this, causing the process to terminate in parsenego_message.
When was CVE-2026-40355 disclosed?
CVE-2026-40355 was first published in the National Vulnerability Database on April 28, 2026, with the most recent update on July 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-40355 actively exploited?
CVE-2026-40355 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 40.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-40355?
CVE-2026-40355 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-40355?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-40355, 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

Explore the affected products and dependency analysis for CVE-2026-40355

Explore →

Is Your Infrastructure Affected by CVE-2026-40355?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs