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
Trending — Patch released this week
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 6.5Exploit: None knownExposed: 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 PROB
1%
EPSS %ILE
43%
KEV
Not listed

Published

June 8, 2026

Last Modified

July 23, 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(12)

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

Patch Availability(12)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntuapache2-utils (2.4.66-2ubuntu2.4) @ resolute2026-08-20ubuntu
ubuntuapache2-utils (2.4.18-2ubuntu3.17+esm19) @ xenial2026-08-20ubuntu
redhatmod_http2-0:2.0.26-2.el9_4.32026-08-18redhat
redhatmod_http2-0:1.15.19-4.el9_2.82026-08-18redhat
redhatinsights-proxy/insights-proxy-container-rhel9:17864336562026-08-11redhat
redhatmod_http2-0:2.0.29-2.el10_0.22026-08-05redhat
redhatmod_http2-0:2.0.26-4.el9_6.22026-08-05redhat
redhathttpd:2.4-8100020260714175253.489197e62026-07-21redhat
redhathttpd-0:2.4.62-13.el9_8.52026-07-20redhat
redhathttpd-0:2.4.63-13.el10_2.42026-07-01redhat
redhatmod_http2-0:2.0.29-4.el10_2.22026-07-01redhat
redhathttpd-main-2.4.68-1.hum12026-06-10redhat

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

(8 across 8 ecosystems)
Alpine:v3.21(1)
PackageVulnerable rangeFixed inDependents
apache2—2.4.68-r0—
Alpine:v3.22(1)
PackageVulnerable rangeFixed inDependents
apache2—2.4.68-r0—
Alpine:v3.23(1)
PackageVulnerable rangeFixed inDependents
apache2—2.4.68-r0—
Alpine:v3.24(1)
PackageVulnerable rangeFixed inDependents
apache2—2.4.68-r0—
Debian:11(1)
PackageVulnerable rangeFixed inDependents
apache22.4.48-3.1 ... 2.4.67-1~deb11u2 (84 versions)2.4.67-1~deb11u3—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
apache22.4.57-2 ... 2.4.67-2 (53 versions)2.4.68-1~deb12u1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
apache22.4.65-2 ... 2.4.68-1~deb12u1 (27 versions)2.4.68-1~deb13u1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
apache22.4.65-2 ... 2.4.68-1~deb13u1 (28 versions)2.4.68-1—

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 19× in last 7d / 91× 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 176 total refreshes for this CVE.

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

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 July 23, 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 1% probability of exploitation in the next 30 days, which ranks it in the top 56.5% of all scored CVEs.
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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