CVE-2026-43951

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

Score 6.5 from GitHub Security Advisory published 2026-06-08. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
6.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 1%CVSS: 6.5Exploit: NoneExposed: 0

A fix is available — apply it.

Out-of-bounds Read vulnerability in Apache HTTP Server with mod_headers and mod_mime and multiple response languages.

This issue affects Apache HTTP Server: from 2.4.0 through 2.4.67.

CVSS v3
6.5
EG Score
6.5(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
Severity65% × 45%
Exploitation1% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
41.3%
KEV
Not listed

Published

June 8, 2026

Last Modified

June 11, 2026

Advisory Details (2)

Auto-updated Jun 13, 2026
⚠️ Active exploitation confirmed. Patch available.
generic

oss-security - CVE-2026-43951: Apache HTTP Server: OOB Read in `merge_response_headers` can cause crash

http://www.openwall.com/lists/oss-security/2026/06/08/10
generic Patch Available🔴 Active Exploitation

Apache HTTP Server 2.4 vulnerabilities - The Apache HTTP Server Project

https://httpd.apache.org/security/vulnerabilities_24.html

Vendor Advisories for CVE-2026-43951(4)

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

Patch Availability(3)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntuapache2-utils (2.4.66-2ubuntu2.4) @ resolute2026-07-15ubuntu
redhathttpd-0:2.4.63-13.el10_2.42026-07-01redhat
redhatmod_http2-0:2.0.29-4.el10_2.22026-07-01redhat

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.

Additional Vendor Advisories

(2)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 8× in last 7d / 56× 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. 2026-07-23 03:14 UTCEG score recompute
  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 14:31 UTCEPSS rescore
  6. 2026-07-19 02:29 UTCEPSS rescore
  7. 2026-07-18 10:04 UTCEPSS rescore
  8. 2026-07-16 17:03 UTCEPSS rescore
  9. 2026-07-15 22:27 UTCVendor advisory
  10. 2026-07-15 22:27 UTCGHSA enrichment
  11. 2026-07-15 16:57 UTCEPSS rescore
  12. 2026-07-15 02:00 UTCEPSS rescore
  13. 2026-07-14 02:49 UTCVendor advisory
  14. 2026-07-14 02:49 UTCGHSA enrichment
  15. 2026-07-13 22:30 UTCEPSS rescore
  16. 2026-07-13 06:13 UTCEPSS rescore
  17. 2026-07-12 05:46 UTCEPSS rescore
  18. 2026-07-11 23:54 UTCVendor advisory
  19. 2026-07-11 23:54 UTCGHSA enrichment
  20. 2026-07-11 08:27 UTCEPSS rescore
  21. 2026-07-10 21:30 UTCVendor advisory
  22. 2026-07-10 21:30 UTCGHSA enrichment
  23. 2026-07-09 19:10 UTCEPSS rescore
  24. 2026-07-09 06:05 UTCVendor advisory
  25. 2026-07-09 06:05 UTCGHSA enrichment
Show 62 more
  1. 2026-07-08 15:16 UTCEPSS rescore
  2. 2026-07-08 03:32 UTCVendor advisory
  3. 2026-07-08 03:32 UTCGHSA enrichment
  4. 2026-07-06 16:27 UTCEPSS rescore
  5. 2026-07-06 02:23 UTCEPSS rescore
  6. 2026-07-05 17:39 UTCVendor advisory
  7. 2026-07-05 17:39 UTCGHSA enrichment
  8. 2026-07-05 02:30 UTCEPSS rescore
  9. 2026-07-04 06:31 UTCEPSS rescore
  10. 2026-07-03 23:42 UTCVendor advisory
  11. 2026-07-03 23:42 UTCGHSA enrichment
  12. 2026-07-02 21:18 UTCVendor advisory
  13. 2026-07-02 21:18 UTCGHSA enrichment
  14. 2026-07-01 18:54 UTCGHSA enrichment
  15. 2026-07-01 15:07 UTCEPSS rescore
  16. 2026-06-30 23:22 UTCEPSS rescore
  17. 2026-06-30 16:30 UTCGHSA enrichment
  18. 2026-06-29 14:06 UTCEPSS rescore
  19. 2026-06-29 08:13 UTCGHSA enrichment
  20. 2026-06-28 14:07 UTCEPSS rescore
  21. 2026-06-28 04:56 UTCEPSS rescore
  22. 2026-06-28 04:31 UTCGHSA enrichment
  23. 2026-06-27 03:08 UTCEPSS rescore
  24. 2026-06-27 02:06 UTCGHSA enrichment
  25. 2026-06-25 23:42 UTCGHSA enrichment
  26. 2026-06-25 13:49 UTCEPSS rescore
  27. 2026-06-25 13:49 UTCEPSS rescore
  28. 2026-06-24 21:18 UTCGHSA enrichment
  29. 2026-06-24 14:05 UTCEPSS rescore
  30. 2026-06-23 21:33 UTCEPSS rescore
  31. 2026-06-23 17:13 UTCGHSA enrichment
  32. 2026-06-22 14:25 UTCEPSS rescore
  33. 2026-06-22 14:25 UTCEPSS rescore
  34. 2026-06-22 14:20 UTCGHSA enrichment
  35. 2026-06-21 14:56 UTCEPSS rescore
  36. 2026-06-21 14:56 UTCEPSS rescore
  37. 2026-06-21 11:52 UTCGHSA enrichment
  38. 2026-06-21 01:59 UTCEPSS rescore
  39. 2026-06-20 08:43 UTCGHSA enrichment
  40. 2026-06-19 19:25 UTCEPSS rescore
  41. 2026-06-19 06:18 UTCGHSA enrichment
  42. 2026-06-18 17:52 UTCEPSS rescore
  43. 2026-06-18 17:52 UTCEPSS rescore
  44. 2026-06-18 03:28 UTCGHSA enrichment
  45. 2026-06-17 17:53 UTCEPSS rescore
  46. 2026-06-17 01:01 UTCGHSA enrichment
  47. 2026-06-16 17:52 UTCEPSS rescore
  48. 2026-06-15 22:38 UTCGHSA enrichment
  49. 2026-06-15 17:49 UTCEPSS rescore
  50. 2026-06-14 20:13 UTCGHSA enrichment
  51. 2026-06-13 23:00 UTCEPSS rescore
  52. 2026-06-13 17:49 UTCGHSA enrichment
  53. 2026-06-12 23:12 UTCEPSS rescore
  54. 2026-06-12 23:12 UTCEPSS rescore
  55. 2026-06-12 15:23 UTCGHSA enrichment
  56. 2026-06-11 14:00 UTCEPSS rescore
  57. 2026-06-11 12:57 UTCEG score recompute▲ 6.50
  58. 2026-06-11 12:57 UTCGHSA enrichment
  59. 2026-06-10 22:18 UTCEPSS rescore
  60. 2026-06-10 13:22 UTCEPSS rescore
  61. 2026-06-10 13:22 UTCEPSS rescore
  62. 2026-06-08 15:43 UTCEG score recompute

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-43951?
CVE-2026-43951 is a medium vulnerability published on June 8, 2026. Out-of-bounds Read vulnerability in Apache HTTP Server with modheaders and modmime and multiple response languages. This issue affects Apache HTTP Server: from 2.4.0 through 2.4.67.
When was CVE-2026-43951 disclosed?
CVE-2026-43951 was first published in the National Vulnerability Database on June 8, 2026, with the most recent update on June 11, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-43951 actively exploited?
CVE-2026-43951 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 41.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-43951?
CVE-2026-43951 has a CVSS v3.1 base score of 6.5 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-43951?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-43951, 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

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