CVE-2026-40542

HIGHPre-NVD 7.37.3—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.3 under CISA-ADP (Vulnrichment) CVSS v3.1 (NVD's own analysis pending). EPSS exploit probability: 0.6%, top 56% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: cisa-adp, epss
Trending — 3 sources updated this week
7.3EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 7.3Exploit: None knownExposed: 0

A fix is available — apply it.

Missing critical step in authentication in Apache HttpClient 5.6 allows an attacker to cause the client to accept SCRAM-SHA-256 authentication without proper mutual authentication verification. Users are recommended to upgrade to version 5.6.1, which fixes this issue.

CVSS v3
7.3
EG Score
7.3(medium)
EG Risk
48(Track)
EG Risk 48/100SSVC: 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
Severity73% × 45%
Exploitation1% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
45%
KEV
Not listed

Published

April 22, 2026

Last Modified

September 9, 2026

Advisory Details (2)

Auto-updated May 1, 2026
No patch confirmed yet.
generic

oss-security - [SECURITY] CVE-2026-40542: Apache HttpClient 5.6 SCRAM-SHA-256 mutual authentication bypass

http://www.openwall.com/lists/oss-security/2026/04/22/5
generic
https://lists.apache.org/thread/tfmgv86xr0z1y096vs3z0y315t1v3o97

Vendor Advisories for CVE-2026-40542(11)

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

Patch Availability(11)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatocp-tools-4/jenkins-rhel8:17865335652026-08-26redhat
redhatocp-tools-4/jenkins-rhel9:17871251662026-08-26redhat
redhatocp-tools-4/jenkins-rhel9:17871246352026-08-26redhat
redhatocp-tools-4/jenkins-rhel9:17871250692026-08-26redhat
redhatocp-tools-4/jenkins-rhel9:17871249252026-08-26redhat
redhatocp-tools-4/jenkins-rhel9:17871253112026-08-26redhat
redhatocp-tools-4/jenkins-rhel8:17866286672026-08-26redhat
redhatocp-tools-4/jenkins-rhel9:17871247792026-08-26redhat
redhatocp-tools-4/jenkins-rhel8:17866286812026-08-26redhat
redhatocp-tools-4/jenkins-rhel8:17865335612026-08-26redhat
redhatocp-tools-4/jenkins-rhel9:17871246322026-08-26redhat

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.

Affected Packages

(1 across 1 ecosystem)
Maven(1)
PackageVulnerable rangeFixed inDependents
org.apache.httpcomponents.client5:httpclient55.6, 5.6-alpha15.6.1—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 38× 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 165 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-40542?
CVE-2026-40542 is a high vulnerability published on April 22, 2026. Missing critical step in authentication in Apache HttpClient 5.6 allows an attacker to cause the client to accept SCRAM-SHA-256 authentication without proper mutual authentication verification. Users are recommended to upgrade to version 5.6.1, which fixes this issue.
When was CVE-2026-40542 disclosed?
CVE-2026-40542 was first published in the National Vulnerability Database on April 22, 2026, with the most recent update on September 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-40542 actively exploited?
CVE-2026-40542 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 55.2% of all scored CVEs.
What is the CVSS score of CVE-2026-40542?
CVE-2026-40542 has a CVSS v3.1 base score of 7.3 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-40542?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-40542, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-40542

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