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Fencer Vulns
high 8.8

CVE-2026-23918 in the critical feed json

Apache HTTP Server: http2: double free and possible RCE on early reset

published 2026-05-04 6 mo ago modified 2026-10-26 13 d ago also BIT-apache-2026-23918 , EUVD-2026-26955

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
49.7%
EPSS 49.7% chance of exploitation in 30 days, percentile 98%
public exploits
1
Exploit-DB

Summary

Double Free and possible RCE vulnerability in Apache HTTP Server with the HTTP/2 protocol.

This issue affects Apache HTTP Server: 2.4.66.

Users are recommended to upgrade to version 2.4.67, which fixes the issue.

Patch / fix

  • bitnami apache 2.4.67
  • Red Hat Red Hat Hardened Images 2.4.67-0.1.hum1
  • apache2 Debian 12 2.4.67-1~deb12u2
  • apache2 Debian 13 2.4.66-1~deb13u2
  • apache2 Debian 14 2.4.66-5

debian advisories DEBIAN-CVE-2026-23918

  • apache2 Ubuntu 26.04 LTS 2.4.66-2ubuntu2.1

ubuntu advisories UBUNTU-CVE-2026-23918

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • httpd hummingbird 1 2.4.67-0.1.hum1
  • httpd-core hummingbird 1 2.4.67-0.1.hum1
  • httpd-tools hummingbird 1 2.4.67-0.1.hum1
  • httpd-manual hummingbird 1 2.4.67-0.1.hum1
  • httpd-filesystem hummingbird 1 2.4.67-0.1.hum1

red hat advisories RHSA-2026:13938

  • apache2 SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +5 more 2.4.66-150400.6.57.1
  • apache2 SLES 16.0, SLES for SAP applications 16.0 2.4.66-160000.2.1
  • apache2-event SLES 16.0, SLES for SAP applications 16.0 2.4.66-160000.2.1
  • apache2-utils SLES 16.0, SLES for SAP applications 16.0 2.4.66-160000.2.1
  • apache2-manual SLES 16.0, SLES for SAP applications 16.0 2.4.66-160000.2.1
  • apache2-worker SLES 16.0, SLES for SAP applications 16.0 2.4.66-160000.2.1
  • apache2-prefork SLES 16.0, SLES for SAP applications 16.0 2.4.66-160000.2.1
  • apache2 SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 2.4.66-35.78.1

suse advisories SUSE-SU-2026:2641-1SUSE-SU-2026:2686-1SUSE-SU-2026:22199-1SUSE-SU-2026:22209-1

  • apache2 openSUSE Leap 16.0 2.4.66-160000.2.1
  • apache2-event openSUSE Leap 16.0 2.4.66-160000.2.1
  • apache2-utils openSUSE Leap 16.0 2.4.66-160000.2.1
  • apache2-manual openSUSE Leap 16.0 2.4.66-160000.2.1
  • apache2-worker openSUSE Leap 16.0 2.4.66-160000.2.1
  • apache2-prefork openSUSE Leap 16.0 2.4.66-160000.2.1
  • apache2 openSUSE Tumbleweed 2.4.67-1.1

opensuse advisories openSUSE-SU-2026:21115-1openSUSE-SU-2026:10785-1

  • apache2 Alpine 3.24, Alpine 3.23, Alpine 3.22 +2 more 2.4.67-r0

alpine advisories ALPINE-CVE-2026-23918

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • httpd Azure Linux 3.0 2.4.67-1

azure linux advisories AZL-86004

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-23918 updated cvss 8.8

Apache HTTP Server: Apache HTTP Server: Remote Code Execution via Double Free in HTTP/2 Protocol

  • Red Hat Hardened Images httpd 2.4.67-0.1.hum1, httpd-core 2.4.67-0.1.hum1, httpd-tools 2.4.67-0.1.hum1, httpd-manual 2.4.67-0.1.hum1, httpd-filesystem 2.4.67-0.1.hum1
    fixed: vendor fix RHSA-2026:13938
  • Red Hat Enterprise Linux 6 httpd, mod_ssl, httpd-tools, httpd-manual Red Hat Enterprise Linux 7 httpd, mod_ssl, mod_ldap, httpd-tools, mod_session, httpd-manual, +1 more Red Hat Enterprise Linux 8 httpd, mod_md, mod_ssl, mod_ldap, mod_http2, httpd-tools, +4 more Red Hat Enterprise Linux 9 httpd, mod_lua, mod_ssl, mod_ldap, mod_http2, httpd-core, +5 more Red Hat Enterprise Linux 10 httpd, mod_http2 Red Hat Hardened Images mod_lua 2.4.67-0.1.hum1, mod_ssl 2.4.67-0.1.hum1, mod_ldap 2.4.67-0.1.hum1, mod_session 2.4.67-0.1.hum1, mod_proxy_html 2.4.67-0.1.hum1
    +1 more products
    Red Hat JBoss Core Services mod_http2
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Timeline

  1. Published
  2. First public exploit (EDB-52577)

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
6 mo ago

Exploit prediction

49.73% chance of exploitation in the next 30 days, higher than 98% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • EDB-52577 Apache HTTP Server 2.4.66 - 'mod_http2' Double-Free Denial of Service webapps, 2026-05-26

CVSS scores

assigned by version score vector
CISA ADP 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
OSV 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
bitnami apache
>=2.4.66, <2.4.67
2.4.67

Affected products

  • Apache Software Foundation Apache HTTP Server
  • Red Hat Red Hat Hardened Images
  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 6
  • Red Hat Red Hat Enterprise Linux 7
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat JBoss Core Services

Classification

Weakness
  • CWE-415 Double Free
  • CWE-1341 Multiple Releases of Same Resource or Handle
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.