Vulnerability · Published Oct 1, 2026 · Assigned by apache
CVE-2026-63686Apache HTTP Server: mod_xml2enc crash on charset conversion failure
High 7.5
In plain English
A high-severity null pointer dereference in Apache HTTP Server from Apache Software Foundation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 40% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.5%top 59.9% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack tooling1Public PoC
Official description
A NULL pointer dereference in mod_xml2enc in Apache Software Foundation Apache HTTP Server before 2.4.69 on all platforms allows an untrusted backend server to cause a denial of service via a proxied response with a charset whose conversion partially succeeds then fails. Users are recommended to upgrade to version 2.4.69, which fixes this issue.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | httpd | 2.4.63-13.el10_2.8 | ALSA-2026:89860 |
| AlmaLinux:8 | httpd | 2.4.37-65.module_el8.10.0+4332+2bef2e0d.13 | ALSA-2026:92616 |
| AlmaLinux:9 | httpd | 2.4.62-13.el9_8.9 | ALSA-2026:88229 |
| AlmaLinux:10 | httpd-core | 2.4.63-13.el10_2.8 | ALSA-2026:89860 |
| AlmaLinux:9 | httpd-core | 2.4.62-13.el9_8.9 | ALSA-2026:88229 |
| AlmaLinux:10 | httpd-devel | 2.4.63-13.el10_2.8 | ALSA-2026:89860 |
| AlmaLinux:8 | httpd-devel | 2.4.37-65.module_el8.10.0+4332+2bef2e0d.13 | ALSA-2026:92616 |
| AlmaLinux:9 | httpd-devel | 2.4.62-13.el9_8.9 | ALSA-2026:88229 |
| AlmaLinux:10 | httpd-filesystem | 2.4.63-13.el10_2.8 | ALSA-2026:89860 |
| AlmaLinux:8 | httpd-filesystem | 2.4.37-65.module_el8.10.0+4332+2bef2e0d.13 | ALSA-2026:92616 |
| AlmaLinux:9 | httpd-filesystem | 2.4.62-13.el9_8.9 | ALSA-2026:88229 |
| AlmaLinux:10 | httpd-manual | 2.4.63-13.el10_2.8 | ALSA-2026:89860 |
| AlmaLinux:8 | httpd-manual | 2.4.37-65.module_el8.10.0+4332+2bef2e0d.13 | ALSA-2026:92616 |
| AlmaLinux:9 | httpd-manual | 2.4.62-13.el9_8.9 | ALSA-2026:88229 |
| AlmaLinux:10 | httpd-tools | 2.4.63-13.el10_2.8 | ALSA-2026:89860 |
| AlmaLinux:8 | httpd-tools | 2.4.37-65.module_el8.10.0+4332+2bef2e0d.13 | ALSA-2026:92616 |
| AlmaLinux:9 | httpd-tools | 2.4.62-13.el9_8.9 | ALSA-2026:88229 |
| AlmaLinux:8 | mod_http2 | 1.15.7-10.module_el8.10.0+4233+8b7d9181.7 | ALSA-2026:92616 |
| AlmaLinux:8 | mod_http2 | 1.15.7-10.module_el8.10.0+4270+e5f13fdb.7 | ALSA-2026:92616 |
| AlmaLinux:10 | mod_ldap | 2.4.63-13.el10_2.8 | ALSA-2026:89860 |
| AlmaLinux:8 | mod_ldap | 2.4.37-65.module_el8.10.0+4332+2bef2e0d.13 | ALSA-2026:92616 |
| AlmaLinux:9 | mod_ldap | 2.4.62-13.el9_8.9 | ALSA-2026:88229 |
| AlmaLinux:10 | mod_lua | 2.4.63-13.el10_2.8 | ALSA-2026:89860 |
| AlmaLinux:9 | mod_lua | 2.4.62-13.el9_8.9 | ALSA-2026:88229 |
| AlmaLinux:8 | mod_md | 1:2.0.8-8.module_el8.10.0+4295+280de5aa.4 | ALSA-2026:92616 |
| AlmaLinux:10 | mod_proxy_html | 1:2.4.63-13.el10_2.8 | ALSA-2026:89860 |
| AlmaLinux:8 | mod_proxy_html | 1:2.4.37-65.module_el8.10.0+4332+2bef2e0d.13 | ALSA-2026:92616 |
| AlmaLinux:9 | mod_proxy_html | 1:2.4.62-13.el9_8.9 | ALSA-2026:88229 |
| AlmaLinux:10 | mod_session | 2.4.63-13.el10_2.8 | ALSA-2026:89860 |
| AlmaLinux:8 | mod_session | 2.4.37-65.module_el8.10.0+4332+2bef2e0d.13 | ALSA-2026:92616 |
| AlmaLinux:9 | mod_session | 2.4.62-13.el9_8.9 | ALSA-2026:88229 |
| AlmaLinux:10 | mod_ssl | 1:2.4.63-13.el10_2.8 | ALSA-2026:89860 |
| AlmaLinux:8 | mod_ssl | 1:2.4.37-65.module_el8.10.0+4332+2bef2e0d.13 | ALSA-2026:92616 |
| AlmaLinux:9 | mod_ssl | 1:2.4.62-13.el9_8.9 | ALSA-2026:88229 |
| Alpine:v3.21 | apache2 | 2.4.69-r0 | ALPINE-CVE-2026-63686 |
| Alpine:v3.22 | apache2 | 2.4.69-r0 | ALPINE-CVE-2026-63686 |
| Alpine:v3.23 | apache2 | 2.4.69-r0 | ALPINE-CVE-2026-63686 |
| Alpine:v3.24 | apache2 | 2.4.69-r0 | ALPINE-CVE-2026-63686 |
| Debian:12 | apache2 | no fix listed | DEBIAN-CVE-2026-63686 |
| Debian:13 | apache2 | 2.4.69-1~deb13u1 | DEBIAN-CVE-2026-63686 |
| Debian:14 | apache2 | 2.4.69-1 | DEBIAN-CVE-2026-63686 |
| Rocky Linux:10 | httpd | 0:2.4.63-13.el10_2.8 | RLSA-2026:89860 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+1830+22f0c9e0 | RLSA-2026:92616 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+40197+0231e209.8 | RLSA-2026:92616 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+1842+4a9649e8.2 | RLSA-2026:92616 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+1938+3b7755d4.3 | RLSA-2026:92616 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+40206+be2c8a50.8 | RLSA-2026:92616 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+40257+286895ef.9 | RLSA-2026:92616 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+1984+1bed3124.4 | RLSA-2026:92616 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+40312+2c72bb9b.10 | RLSA-2026:92616 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+2061+8d03fdec.5 | RLSA-2026:92616 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+40402+af9563a3.13 | RLSA-2026:92616 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+40045+6ce8579b.6 | RLSA-2026:92616 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+40053+5a18018e.7 | RLSA-2026:92616 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+1840+b070a976.1 | RLSA-2026:92616 |
| Rocky Linux:9 | httpd | 0:2.4.62-13.el9_8.9 | RLSA-2026:88229 |
| Rocky Linux:8 | mod_http2 | 0:1.15.7-10.module+el8.10.0+40257+286895ef.7 | RLSA-2026:92616 |
| Rocky Linux:8 | mod_http2 | 0:1.15.7-10.module+el8.10.0+40204+716978aa.6 | RLSA-2026:92616 |
| Rocky Linux:8 | mod_http2 | 0:1.15.7-10.module+el8.10.0+40197+0231e209.5 | RLSA-2026:92616 |
| Rocky Linux:8 | mod_http2 | 0:1.15.7-10.module+el8.10.0+2061+8d03fdec.4 | RLSA-2026:92616 |
| Rocky Linux:8 | mod_http2 | 0:1.15.7-10.module+el8.10.0+1938+3b7755d4.3 | RLSA-2026:92616 |
| Rocky Linux:8 | mod_http2 | 0:1.15.7-10.module+el8.10.0+1883+38ed6c58.1 | RLSA-2026:92616 |
| Rocky Linux:8 | mod_http2 | 0:1.15.7-10.module+el8.10.0+1830+22f0c9e0 | RLSA-2026:92616 |
| Rocky Linux:8 | mod_http2 | 0:1.15.7-10.module+el8.10.0+1775+6b057638 | RLSA-2026:92616 |
| Rocky Linux:8 | mod_md | 1:2.0.8-8.module+el8.10.0+40053+5a18018e.2 | RLSA-2026:92616 |
| Rocky Linux:8 | mod_md | 1:2.0.8-8.module+el8.9.0+1370+89cc8ad5 | RLSA-2026:92616 |
| Rocky Linux:8 | mod_md | 1:2.0.8-8.module+el8.10.0+40369+03c444c1.4 | RLSA-2026:92616 |
| Ubuntu:22.04:LTS | apache2 | 2.4.52-1ubuntu4.25 | USN-8931-1 |
| Ubuntu:22.04:LTS | apache2 | 2.4.52-1ubuntu4.25 | UBUNTU-CVE-2026-63686 |
| Ubuntu:24.04:LTS | apache2 | 2.4.58-1ubuntu8.17 | USN-8931-1 |
| Ubuntu:24.04:LTS | apache2 | 2.4.58-1ubuntu8.17 | UBUNTU-CVE-2026-63686 |
| Ubuntu:26.04:LTS | apache2 | 2.4.66-2ubuntu2.6 | UBUNTU-CVE-2026-63686 |
| Ubuntu:26.04:LTS | apache2 | 2.4.66-2ubuntu2.6 | USN-8931-1 |
| Ubuntu:26.10 | apache2 | no fix listed | UBUNTU-CVE-2026-63686 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Apache Software Foundation | Apache HTTP Server | 2.4.0 – through 2.4.68 |
Weakness: CWE-476 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H