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Fencer Vulns
high 7.3

CVE-2026-73637 json

Apache HTTP Server: mod_auth_digest DoS attack

published 2026-10-01 38 d ago modified 2026-10-06 33 d ago also BIT-apache-2026-73637 , EUVD-2026-90908

cvss
7.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 40%
public exploits
0
none known

Summary

Use after free in mod_auth_digest in Apache Software Foundation Apache HTTP Server before 2.4.69 on all platforms allows an unauthenticated remote client to cause authentication state corruption via concurrent Digest authentication requests when AuthDigestNcCheck is enabled or AuthDigestNonceLifetime is set to 0.

Users are recommended to upgrade to version 2.4.69, which fixes this issue.

Patch / fix

  • bitnami apache 2.4.69
  • apache http_server 2.4.69
  • apache2 Debian 13 2.4.69-1~deb13u1
  • apache2 Debian 14 2.4.69-1

debian advisories DEBIAN-CVE-2026-73637

  • apache2 Ubuntu 22.04 LTS 2.4.52-1ubuntu4.25
  • apache2 Ubuntu 24.04 LTS 2.4.58-1ubuntu8.17
  • apache2 Ubuntu 26.04 LTS 2.4.66-2ubuntu2.6
  • apache2 Ubuntu Pro 14.04 LTS 2.4.7-1ubuntu4.22+esm17
  • apache2 Ubuntu Pro 16.04 LTS 2.4.18-2ubuntu3.17+esm22
  • apache2 Ubuntu Pro 18.04 LTS 2.4.29-1ubuntu4.27+esm13
  • apache2 Ubuntu Pro 20.04 LTS 2.4.41-4ubuntu3.23+esm9

ubuntu advisories UBUNTU-CVE-2026-73637

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 2.4.69-1.hum1
  • mod_lua hummingbird 1 2.4.69-1.hum1
  • mod_ssl hummingbird 1 2.4.69-1.hum1
  • mod_ldap hummingbird 1 2.4.69-1.hum1
  • httpd-core hummingbird 1 2.4.69-1.hum1
  • httpd-tools hummingbird 1 2.4.69-1.hum1
  • mod_session hummingbird 1 2.4.69-1.hum1
  • httpd-manual hummingbird 1 2.4.69-1.hum1

red hat advisories RHSA-2026:74858

  • apache2 SLE Module for Basesystem 15 SP7 2.4.66-150700.4.26.1
  • apache2-event SLE Module for Package Hub 15 SP7 2.4.66-150700.4.26.1
  • apache2-utils SLE Module for Server Applications 15 SP7 2.4.66-150700.4.26.1
  • apache2-manual SLE Module for Server Applications 15 SP7 2.4.66-150700.4.26.1
  • apache2-worker SLE Module for Server Applications 15 SP7 2.4.66-150700.4.26.1
  • apache2-prefork SLE Module for Basesystem 15 SP7 2.4.66-150700.4.26.1
  • apache2 SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +5 more 2.4.66-150400.6.60.1
  • apache2 SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 2.4.66-35.84.1

suse advisories SUSE-SU-2026:5099-1SUSE-SU-2026:5077-1SUSE-SU-2026:5076-1SUSE-SU-2026:5075-1

  • httpd AlmaLinux 8 2.4.37-65.module_el8.10.0+4332+2bef2e0d.13
  • mod_md AlmaLinux 8 1:2.0.8-8.module_el8.10.0+4295+280de5aa.4
  • mod_ssl AlmaLinux 8 1:2.4.37-65.module_el8.10.0+4332+2bef2e0d.13
  • mod_ldap AlmaLinux 8 2.4.37-65.module_el8.10.0+4332+2bef2e0d.13
  • mod_http2 AlmaLinux 8 1.15.7-10.module_el8.10.0+4233+8b7d9181.7
  • mod_http2 AlmaLinux 8 1.15.7-10.module_el8.10.0+4270+e5f13fdb.7
  • httpd-tools AlmaLinux 8 2.4.37-65.module_el8.10.0+4332+2bef2e0d.13
  • mod_session AlmaLinux 8 2.4.37-65.module_el8.10.0+4332+2bef2e0d.13

almalinux advisories ALSA-2026:92616ALSA-2026:89860ALSA-2026:88229

  • httpd Rocky Linux 8 2.4.37-65.module+el8.10.0+40197+0231e209.8
  • httpd Rocky Linux 8 2.4.37-65.module+el8.10.0+1842+4a9649e8.2
  • httpd Rocky Linux 8 2.4.37-65.module+el8.10.0+1938+3b7755d4.3
  • httpd Rocky Linux 8 2.4.37-65.module+el8.10.0+40206+be2c8a50.8
  • httpd Rocky Linux 8 2.4.37-65.module+el8.10.0+40257+286895ef.9
  • httpd Rocky Linux 8 2.4.37-65.module+el8.10.0+1984+1bed3124.4
  • httpd Rocky Linux 8 2.4.37-65.module+el8.10.0+40312+2c72bb9b.10
  • httpd Rocky Linux 8 2.4.37-65.module+el8.10.0+2061+8d03fdec.5

rocky linux advisories RLSA-2026:92616RLSA-2026:89860RLSA-2026:88229

  • apache2 Alpine 3.24, Alpine 3.23, Alpine 3.22 +1 more 2.4.69-r0

alpine advisories ALPINE-CVE-2026-73637

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 2.4.69-1

azure linux advisories AZL-106785

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-2026-73637 updated cvss 5.6

httpd: httpd: Authentication state corruption via concurrent Digest authentication requests

  • Red Hat Enterprise Linux 7 httpd, mod_ssl, mod_ldap, httpd-tools, mod_session, httpd-manual, +1 more
    affected: workaround, no fix available
  • Red Hat JBoss Core Services jbcs-httpd24-httpd, jbcs-httpd24-mod_md, jbcs-httpd24-mod_ssl, jbcs-httpd24-mod_ldap, jbcs-httpd24-httpd-zip, jbcs-httpd24-httpd-libs, +6 more
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Enterprise Linux AppStream (v. 8) mod_md 2.0.8-8.module+el8.10.0+24941+3af7c60a.4, httpd 2.4.37-65.module+el8.10.0+25092+6f3ea0dd.13, mod_ssl 2.4.37-65.module+el8.10.0+25092+6f3ea0dd.13, mod_http2 1.15.7-10.module+el8.10.0+24521+219dcfc5.7, mod_ldap 2.4.37-65.module+el8.10.0+25092+6f3ea0dd.13, httpd-tools 2.4.37-65.module+el8.10.0+25092+6f3ea0dd.13, +4 more
    fixed: vendor fix RHSA-2026:92616
  • Red Hat Enterprise Linux AppStream (v. 9) httpd 2.4.62-13.el9_8.9, mod_lua 2.4.62-13.el9_8.9, mod_ssl 2.4.62-13.el9_8.9, mod_ldap 2.4.62-13.el9_8.9, httpd-core 2.4.62-13.el9_8.9, httpd-tools 2.4.62-13.el9_8.9, +4 more
    fixed: vendor fix RHSA-2026:88229
  • Red Hat Enterprise Linux AppStream (v. 10) httpd 2.4.63-13.el10_2.8, mod_lua 2.4.63-13.el10_2.8, mod_ssl 2.4.63-13.el10_2.8, mod_ldap 2.4.63-13.el10_2.8, httpd-core 2.4.63-13.el10_2.8, httpd-tools 2.4.63-13.el10_2.8, +4 more
    fixed: vendor fix RHSA-2026:89860
  • Red Hat Hardened Images httpd 2.4.69-1.hum1, mod_lua 2.4.69-1.hum1, mod_ssl 2.4.69-1.hum1, mod_ldap 2.4.69-1.hum1, httpd-core 2.4.69-1.hum1, httpd-tools 2.4.69-1.hum1, +4 more
    fixed: vendor fix RHSA-2026:74858
  • Red Hat Enterprise Linux 6 httpd, mod_ssl, httpd-tools, httpd-manual
    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

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
38 d ago

Exploit prediction

0.47% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
CNA 3.1 7.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
OSV 3.1 7.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Affected packages

ecosystem package affected fixed in
bitnami apache
>=2.4.0, <2.4.69
2.4.69

Affected products

  • Apache Software Foundation Apache HTTP Server

Classification

Weakness
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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.