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TI-2026-32006 Aliases CVE-2026-43951GHSA-4qxr-h6g3-8f95

Apache HTTP Server: OOB Read in `merge_response_headers` can cause crash

Priority LOW 36CWE-125Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
Low · Low · None
Fix status
Partial Red Hat: 11 fixed, 3 without a fix

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00545 45th percentileScored 2026-11-07
Fix Partial Red Hat: 16 advisoriesRed Hat: 11 fixed, 3 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
ApacheApache HTTP Server2.4.0 – 2.4.67—No fix listedCNA
  • Apache HTTP Server VendorApache Affected 2.4.0 – 2.4.67 Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*2.4.0 – 2.4.67VulnerableApache
  • cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:* Versions 2.4.0 – 2.4.67 Vulnerable ·Apache

Remediation

Red Hat 16 advisories

  • RHSA-2026:67152 Released 2026-09-14 · Red Hat rating Important
    httpd security update
    • Red Hat Enterprise Linux AppStream E4S (v.9.2) httpd-2.4.53-11.el9_2.15, httpd-core-2.4.53-11.el9_2.15, mod_ldap-2.4.53-11.el9_2.15 +2
  • RHSA-2026:66323 Released 2026-09-10 · Red Hat rating Important
    httpd security update
    • Red Hat Enterprise Linux AppStream E4S (v.9.4) httpd-2.4.57-11.el9_4.5, httpd-core-2.4.57-11.el9_4.5, mod_ldap-2.4.57-11.el9_4.5 +2
  • RHSA-2026:62165 Released 2026-09-01 · Red Hat rating Important
    httpd security update
    • Red Hat Enterprise Linux AppStream EUS (v.9.6) httpd-2.4.62-4.el9_6.6, httpd-core-2.4.62-4.el9_6.6, httpd-devel-2.4.62-4.el9_6.6 +8
Show 13 more Red Hat advisories
  • RHSA-2026:59387 Released 2026-08-25 · Red Hat rating Moderate
    mod_http2 security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 9) mod_http2-2.0.26-6.el9_8.2
  • RHSA-2026:56868 Released 2026-08-19 · Red Hat rating Important
    Red Hat JBoss Core Services Apache HTTP Server 2.4.62 SP5 security update
    • Red Hat JBoss Core Services on RHEL 8 jbcs-httpd24-httpd-2.4.62-16.el8jbcs, jbcs-httpd24-httpd-devel-2.4.62-16.el8jbcs, jbcs-httpd24-httpd-manual-2.4.62-16.el8jbcs +7
  • RHSA-2026:56869 Released 2026-08-19 · Red Hat rating Important
    Red Hat JBoss Core Services Apache HTTP Server 2.4.62 SP5 security update
    • Red Hat JBoss Core Services 2.4.62.SP5
  • RHSA-2026:55992 Released 2026-08-18 · Red Hat rating Important
    mod_http2 security update
    • Red Hat Enterprise Linux AppStream E4S (v.9.4) mod_http2-2.0.26-2.el9_4.3
  • RHSA-2026:55930 Released 2026-08-18 · Red Hat rating Important
    mod_http2 security update
    • Red Hat Enterprise Linux AppStream E4S (v.9.2) mod_http2-1.15.19-4.el9_2.8
  • RHSA-2026:53371 Released 2026-08-11 · Red Hat rating Important
    Insights proxy Container Image
    • Red Hat Insights proxy 1.5 registry.redhat.io/insights-proxy/insights-proxy-container-rhel9
  • RHSA-2026:50572 Released 2026-08-05 · Red Hat rating Important
    mod_http2 security update
    • Red Hat Enterprise Linux AppStream EUS (v.9.6) mod_http2-2.0.26-4.el9_6.2
  • RHSA-2026:50538 Released 2026-08-05 · Red Hat rating Important
    mod_http2 security update
    • Red Hat Enterprise Linux AppStream EUS (v. 10.0) mod_http2-2.0.29-2.el10_0.2
  • RHSA-2026:42828 Released 2026-07-21 · Red Hat rating Important
    httpd:2.4 security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 8) httpd-2.4.37-65.module+el8.10.0+24521+219dcfc5.9.aarch64::httpd:2.4, httpd-2.4.37-65.module+el8.10.0+24521+219dcfc5.9.ppc64le::httpd:2.4, httpd-2.4.37-65.module+el8.10.0+24521+219dcfc5.9.s390x::httpd:2.4 +38
  • RHSA-2026:41906 Released 2026-07-20 · Red Hat rating Important
    httpd security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 9) httpd-2.4.62-13.el9_8.5, httpd-core-2.4.62-13.el9_8.5, httpd-devel-2.4.62-13.el9_8.5 +8
  • RHSA-2026:34355 Released 2026-07-01 · Red Hat rating Moderate
    mod_http2 security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 10) mod_http2-2.0.29-4.el10_2.2
  • RHSA-2026:34109 Released 2026-07-01 · Red Hat rating Important
    httpd security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 10) httpd-2.4.63-13.el10_2.4, httpd-core-2.4.63-13.el10_2.4, httpd-devel-2.4.63-13.el10_2.4 +8
  • RHSA-2026:25042 Released 2026-06-10 · Red Hat rating Important
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images httpd-2.4.68-1.hum1@aarch64, httpd-2.4.68-1.hum1@src, httpd-2.4.68-1.hum1@x86_64 +10

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 7AffectedNo fix planned: Out of support scope
Red Hat JBoss Core ServicesAffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:34109, RHSA-2026:34355
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2026:42828
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:41906, RHSA-2026:59387
Red Hat Enterprise Linux AppStream E4S (v.9.2)Fixed RHSA-2026:55930, RHSA-2026:67152
Red Hat Enterprise Linux AppStream E4S (v.9.4)Fixed RHSA-2026:55992, RHSA-2026:66323
Red Hat Enterprise Linux AppStream EUS (v. 10.0)Fixed RHSA-2026:50538
Red Hat Enterprise Linux AppStream EUS (v.9.6)Fixed RHSA-2026:50572, RHSA-2026:62165
Red Hat Hardened ImagesFixed RHSA-2026:25042
Red Hat Insights proxy 1.5Fixed RHSA-2026:53371
Red Hat JBoss Core Services 2.4.62.SP5Fixed RHSA-2026:56869
Red Hat JBoss Core Services on RHEL 8Fixed RHSA-2026:56868
Not affected: 6 products
  • Red Hat Enterprise Linux AppStream E4S (v.9.2)
  • Red Hat Enterprise Linux AppStream E4S (v.9.4)
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • Red Hat Enterprise Linux AppStream EUS (v.9.6)
  • Red Hat Hardened Images
  • Red Hat JBoss Core Services on RHEL 8

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-43951
  2. 2026-10-03 Alias added: GHSA-4qxr-h6g3-8f95
  3. 2026-10-09 Fix available: RHSA-2026:56869 · Red Hat
  4. 2026-10-09 Fix available: Red Hat JBoss Core Services 2.4.62.SP5 · Red Hat
  5. 2026-10-16 Affected versions changed · Red Hat
  6. 2026-10-25 EPSS moved to the below the 50th percentile

References

Advisory 2

  • TI-2021-18535 Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) KEVCVSS 3.1CRITICAL 9.8
  • TI-2021-18417 Path traversal and file disclosure vulnerability in Apache HTTP Server 2.4.49 KEVCVSS 3.1CRITICAL 9.8
  • TI-2024-25716 Apache HTTP Server weakness in mod_rewrite when first segment of substitution matches filesystem path. KEVCVSS 3.1CRITICAL 9.1
  • TI-2021-17490 mod_proxy SSRF KEVCVSS 3.1CRITICAL 9.0
  • TI-2019-00184 Use after free in Apache HTTP Server KEVCVSS 3.1HIGH 7.8
  • TI-2009-03392 The TLS protocol, and the SSL protocol 3.0 and possibly earlier, as used in Microsoft… CVSS 3.1CRITICAL 9.8
See all 349 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences