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TI-2026-36808 Aliases CVE-2026-49975GHSA-262v-g5h9-6mc6

Apache HTTP Server: mod_http2 denial of service

Priority HIGH 72CWE-789Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat. Impact type from CWE-789.

Summary

Memory Allocation with Excessive Size Value vulnerability in Apache HTTP Server's mod_http leads to denial of service via malicious HTTP requests. This issue affects Apache HTTP Server: from 2.4.17 through 2.4.67.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.3295 98th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed Red Hat: 14 advisories

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
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 Server2.4.17 – 2.4.67—No fix listedCNA
  • Apache HTTP Server VendorApache Affected 2.4.17 – 2.4.67 Fixed in — No fix listed CNA

CPE configurations NVD · 2

CPEVersionsRoleVendor
cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*2.4.17 to before 2.4.68VulnerableApache
cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*11.0VulnerableDebian
  • cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:* Versions 2.4.17 to before 2.4.68 Vulnerable ·Apache
  • cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* Versions 11.0 Vulnerable ·Debian

Remediation

Red Hat 14 advisories

  • 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-2026:50572 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
Show 11 more Red Hat advisories
  • 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-2026:36846 Released 2026-07-08 · Red Hat rating Important
    httpd:2.4 security update
    • Red Hat Enterprise Linux AppStream AUS (v.8.4) httpd-2.4.37-39.module+el8.4.0+24495+1afced82.12.src::httpd:2.4, httpd-2.4.37-39.module+el8.4.0+24495+1afced82.12.x86_64::httpd:2.4, httpd-devel-2.4.37-39.module+el8.4.0+24495+1afced82.12.x86_64::httpd:2.4 +11
    • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) httpd-2.4.37-39.module+el8.4.0+24495+1afced82.12.src::httpd:2.4, httpd-2.4.37-39.module+el8.4.0+24495+1afced82.12.x86_64::httpd:2.4, httpd-devel-2.4.37-39.module+el8.4.0+24495+1afced82.12.x86_64::httpd:2.4 +11
  • RHSA-2026:36831 Released 2026-07-08 · Red Hat rating Important
    httpd:2.4 security update
    • Red Hat Enterprise Linux AppStream AUS (v.8.6) httpd-2.4.37-47.module+el8.6.0+24496+af8fe930.13.src::httpd:2.4, httpd-2.4.37-47.module+el8.6.0+24496+af8fe930.13.x86_64::httpd:2.4, httpd-devel-2.4.37-47.module+el8.6.0+24496+af8fe930.13.x86_64::httpd:2.4 +11
    • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6) httpd-2.4.37-47.module+el8.6.0+24496+af8fe930.13.src::httpd:2.4, httpd-2.4.37-47.module+el8.6.0+24496+af8fe930.13.x86_64::httpd:2.4, httpd-devel-2.4.37-47.module+el8.6.0+24496+af8fe930.13.x86_64::httpd:2.4 +11
  • RHSA-2026:36373 Released 2026-07-07 · Red Hat rating Important
    httpd:2.4 security update
    • Red Hat Enterprise Linux AppStream E4S (v.8.8) httpd-2.4.37-56.module+el8.8.0+24497+e470c0e2.12.ppc64le::httpd:2.4, httpd-2.4.37-56.module+el8.8.0+24497+e470c0e2.12.src::httpd:2.4, httpd-2.4.37-56.module+el8.8.0+24497+e470c0e2.12.x86_64::httpd:2.4 +20
    • Red Hat Enterprise Linux AppStream TUS (v.8.8) httpd-2.4.37-56.module+el8.8.0+24497+e470c0e2.12.src::httpd:2.4, httpd-2.4.37-56.module+el8.8.0+24497+e470c0e2.12.x86_64::httpd:2.4, httpd-devel-2.4.37-56.module+el8.8.0+24497+e470c0e2.12.x86_64::httpd:2.4 +11
  • RHSA-2026:27200 Released 2026-06-22 · Red Hat rating Important
    Red Hat JBoss Core Services Apache HTTP Server 2.4.62 SP4 security update
    • Red Hat JBoss Core Services on RHEL 7 Server jbcs-httpd24-httpd-2.4.62-13.el7jbcs, jbcs-httpd24-httpd-devel-2.4.62-13.el7jbcs, jbcs-httpd24-httpd-manual-2.4.62-13.el7jbcs +10
    • Red Hat JBoss Core Services on RHEL 8 jbcs-httpd24-httpd-2.4.62-13.el8jbcs, jbcs-httpd24-httpd-devel-2.4.62-13.el8jbcs, jbcs-httpd24-httpd-manual-2.4.62-13.el8jbcs +10
  • RHSA-2026:27201 Released 2026-06-22 · Red Hat rating Important
    Red Hat JBoss Core Services Apache HTTP Server 2.4.62 SP4 security update
    • Red Hat JBoss Core Services 2.4.62.SP4
  • RHSA-2026:27114 Released 2026-06-18 · Red Hat rating Important
    Red Hat OpenShift Service Mesh 2.6.17
    • Red Hat OpenShift Service Mesh 2.6 registry.redhat.io/openshift-service-mesh/proxyv2-rhel9
  • RHSA-2026:25225 Released 2026-06-11 · Red Hat rating Important
    mod_http2 security update
    • Red Hat Enterprise Linux AppStream (v. 10) mod_http2-2.0.29-4.el10_2.1
  • RHSA-2026:25090 Released 2026-06-10 · Red Hat rating Important
    httpd:2.4 security update
    • Red Hat Enterprise Linux AppStream (v. 8) httpd-2.4.37-65.module+el8.10.0+24281+ea10630c.8.aarch64::httpd:2.4, httpd-2.4.37-65.module+el8.10.0+24281+ea10630c.8.ppc64le::httpd:2.4, httpd-2.4.37-65.module+el8.10.0+24281+ea10630c.8.s390x::httpd:2.4 +38
  • RHSA-2026:25057 Released 2026-06-10 · Red Hat rating Important
    mod_http2 security update
    • Red Hat Enterprise Linux AppStream (v. 9) mod_http2-2.0.26-6.el9_8.1
  • 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: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:25225
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2026:25090
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:25057
Red Hat Enterprise Linux AppStream AUS (v.8.4)Fixed RHSA-2026:36846
Red Hat Enterprise Linux AppStream AUS (v.8.6)Fixed RHSA-2026:36831
Red Hat Enterprise Linux AppStream E4S (v.8.8)Fixed RHSA-2026:36373
Red Hat Enterprise Linux AppStream E4S (v.9.2)Fixed RHSA-2026:55930
Red Hat Enterprise Linux AppStream E4S (v.9.4)Fixed RHSA-2026:55992
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
Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4)Fixed RHSA-2026:36846
Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6)Fixed RHSA-2026:36831
Red Hat Enterprise Linux AppStream TUS (v.8.8)Fixed RHSA-2026:36373
Red Hat Hardened ImagesFixed RHSA-2026:25042
Red Hat JBoss Core Services 2.4.62.SP4Fixed RHSA-2026:27201
Red Hat JBoss Core Services on RHEL 7 ServerFixed RHSA-2026:27200
Red Hat JBoss Core Services on RHEL 8Fixed RHSA-2026:27200
Red Hat OpenShift Service Mesh 2.6Fixed RHSA-2026:27114
Not affected: 10 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
  • Red Hat JBoss Core Services on RHEL 7 Server
  • Red Hat JBoss Core Services on RHEL 8
  • Red Hat JBoss Web Server 5
  • Red Hat OpenShift Service Mesh 2.6

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-49975
  2. 2026-10-03 Alias added: GHSA-262v-g5h9-6mc6
  3. 2026-10-09 Fix available: RHSA-2026:27201 · Red Hat
  4. 2026-10-16 Fix available: Red Hat JBoss Core Services 2.4.62.SP4 · Red Hat
  5. 2026-10-25 EPSS moved to the 95th–99th percentile

References

Exploit 1

Advisory 4

  • 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