Vulnerability · Published Jun 8, 2026 · Assigned by apache
CVE-2026-42536Apache HTTP Server: mod_xml2enc heap overflow
High 7.5
In plain English
A high-severity heap buffer overflow 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 1.0% (higher than 64% 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)1.0%top 36.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack tooling1Public PoC
Official description
Heap-based Buffer Overflow vulnerability in Apache HTTP Server with mod_xml2enc, xml2StartParse, and untrusted content This issue affects Apache HTTP Server: from 2.4.0 through 2.4.67. Users are recommended to upgrade to version 2.4.68, which fixes the issue.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | httpd | 2.4.63-13.el10_2.4 | ALSA-2026:34109 |
| AlmaLinux:8 | httpd | 2.4.37-65.module_el8.10.0+4233+8b7d9181.9 | ALSA-2026:42828 |
| AlmaLinux:9 | httpd | 2.4.62-13.el9_8.5 | ALSA-2026:41906 |
| AlmaLinux:10 | httpd-core | 2.4.63-13.el10_2.4 | ALSA-2026:34109 |
| AlmaLinux:9 | httpd-core | 2.4.62-13.el9_8.5 | ALSA-2026:41906 |
| AlmaLinux:10 | httpd-devel | 2.4.63-13.el10_2.4 | ALSA-2026:34109 |
| AlmaLinux:8 | httpd-devel | 2.4.37-65.module_el8.10.0+4233+8b7d9181.9 | ALSA-2026:42828 |
| AlmaLinux:9 | httpd-devel | 2.4.62-13.el9_8.5 | ALSA-2026:41906 |
| AlmaLinux:10 | httpd-filesystem | 2.4.63-13.el10_2.4 | ALSA-2026:34109 |
| AlmaLinux:9 | httpd-filesystem | 2.4.62-13.el9_8.5 | ALSA-2026:41906 |
| AlmaLinux:10 | httpd-manual | 2.4.63-13.el10_2.4 | ALSA-2026:34109 |
| AlmaLinux:8 | httpd-manual | 2.4.37-65.module_el8.10.0+4233+8b7d9181.9 | ALSA-2026:42828 |
| AlmaLinux:9 | httpd-manual | 2.4.62-13.el9_8.5 | ALSA-2026:41906 |
| AlmaLinux:10 | httpd-tools | 2.4.63-13.el10_2.4 | ALSA-2026:34109 |
| AlmaLinux:8 | httpd-tools | 2.4.37-65.module_el8.10.0+4233+8b7d9181.9 | ALSA-2026:42828 |
| AlmaLinux:9 | httpd-tools | 2.4.62-13.el9_8.5 | ALSA-2026:41906 |
| AlmaLinux:8 | mod_http2 | 1.15.7-10.module_el8.10.0+4233+8b7d9181.7 | ALSA-2026:42828 |
| AlmaLinux:10 | mod_ldap | 2.4.63-13.el10_2.4 | ALSA-2026:34109 |
| AlmaLinux:8 | mod_ldap | 2.4.37-65.module_el8.10.0+4233+8b7d9181.9 | ALSA-2026:42828 |
| AlmaLinux:9 | mod_ldap | 2.4.62-13.el9_8.5 | ALSA-2026:41906 |
| AlmaLinux:10 | mod_lua | 2.4.63-13.el10_2.4 | ALSA-2026:34109 |
| AlmaLinux:9 | mod_lua | 2.4.62-13.el9_8.5 | ALSA-2026:41906 |
| AlmaLinux:8 | mod_md | 1:2.0.8-8.module_el8.10.0+4088+57f011c1.2 | ALSA-2026:42828 |
| AlmaLinux:10 | mod_proxy_html | 1:2.4.63-13.el10_2.4 | ALSA-2026:34109 |
| AlmaLinux:8 | mod_proxy_html | 1:2.4.37-65.module_el8.10.0+4233+8b7d9181.9 | ALSA-2026:42828 |
| AlmaLinux:9 | mod_proxy_html | 1:2.4.62-13.el9_8.5 | ALSA-2026:41906 |
| AlmaLinux:10 | mod_session | 2.4.63-13.el10_2.4 | ALSA-2026:34109 |
| AlmaLinux:8 | mod_session | 2.4.37-65.module_el8.10.0+4233+8b7d9181.9 | ALSA-2026:42828 |
| AlmaLinux:9 | mod_session | 2.4.62-13.el9_8.5 | ALSA-2026:41906 |
| AlmaLinux:10 | mod_ssl | 1:2.4.63-13.el10_2.4 | ALSA-2026:34109 |
| AlmaLinux:8 | mod_ssl | 1:2.4.37-65.module_el8.10.0+4233+8b7d9181.9 | ALSA-2026:42828 |
| AlmaLinux:9 | mod_ssl | 1:2.4.62-13.el9_8.5 | ALSA-2026:41906 |
| Alpine:v3.21 | apache2 | 2.4.68-r0 | ALPINE-CVE-2026-42536 |
| Alpine:v3.22 | apache2 | 2.4.68-r0 | ALPINE-CVE-2026-42536 |
| Alpine:v3.23 | apache2 | 2.4.68-r0 | ALPINE-CVE-2026-42536 |
| Alpine:v3.24 | apache2 | 2.4.68-r0 | ALPINE-CVE-2026-42536 |
| Debian:12 | apache2 | 2.4.68-1~deb12u1 | DEBIAN-CVE-2026-42536 |
| Debian:13 | apache2 | 2.4.68-1~deb13u1 | DEBIAN-CVE-2026-42536 |
| Debian:14 | apache2 | 2.4.68-1 | DEBIAN-CVE-2026-42536 |
| Rocky Linux:10 | httpd | 0:2.4.63-13.el10_2.4 | RLSA-2026:34109 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+2061+8d03fdec.5 | RLSA-2026:42828 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+1984+1bed3124.4 | RLSA-2026:42828 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+1938+3b7755d4.3 | RLSA-2026:42828 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+40045+6ce8579b.6 | RLSA-2026:42828 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+40206+be2c8a50.8 | RLSA-2026:42828 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+40053+5a18018e.7 | RLSA-2026:42828 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+1830+22f0c9e0 | RLSA-2026:42828 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+1842+4a9649e8.2 | RLSA-2026:42828 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+1840+b070a976.1 | RLSA-2026:42828 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+40197+0231e209.8 | RLSA-2026:42828 |
| Rocky Linux:9 | httpd | 0:2.4.62-13.el9_8.5 | RLSA-2026:41906 |
| Rocky Linux:8 | mod_http2 | 0:1.15.7-10.module+el8.10.0+2061+8d03fdec.4 | RLSA-2026:42828 |
| Rocky Linux:8 | mod_http2 | 0:1.15.7-10.module+el8.10.0+1883+38ed6c58.1 | RLSA-2026:42828 |
| Rocky Linux:8 | mod_http2 | 0:1.15.7-10.module+el8.10.0+40197+0231e209.5 | RLSA-2026:42828 |
| Rocky Linux:8 | mod_http2 | 0:1.15.7-10.module+el8.10.0+1830+22f0c9e0 | RLSA-2026:42828 |
| Rocky Linux:8 | mod_http2 | 0:1.15.7-10.module+el8.10.0+1938+3b7755d4.3 | RLSA-2026:42828 |
| Rocky Linux:8 | mod_http2 | 0:1.15.7-10.module+el8.10.0+1775+6b057638 | RLSA-2026:42828 |
| Rocky Linux:8 | mod_http2 | 0:1.15.7-10.module+el8.10.0+40204+716978aa.6 | RLSA-2026:42828 |
| Rocky Linux:8 | mod_md | 1:2.0.8-8.module+el8.9.0+1370+89cc8ad5 | RLSA-2026:42828 |
| Rocky Linux:8 | mod_md | 1:2.0.8-8.module+el8.10.0+40053+5a18018e.2 | RLSA-2026:42828 |
| Ubuntu:22.04:LTS | apache2 | 2.4.52-1ubuntu4.23 | USN-8516-1 |
| Ubuntu:22.04:LTS | apache2 | 2.4.52-1ubuntu4.23 | UBUNTU-CVE-2026-42536 |
| Ubuntu:24.04:LTS | apache2 | 2.4.58-1ubuntu8.15 | UBUNTU-CVE-2026-42536 |
| Ubuntu:24.04:LTS | apache2 | 2.4.58-1ubuntu8.15 | USN-8516-1 |
| Ubuntu:25.10 | apache2 | no fix listed | UBUNTU-CVE-2026-42536 |
| Ubuntu:26.04:LTS | apache2 | 2.4.66-2ubuntu2.4 | USN-8516-1 |
| Ubuntu:26.04:LTS | apache2 | 2.4.66-2ubuntu2.4 | UBUNTU-CVE-2026-42536 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Apache Software Foundation | Apache HTTP Server | 2.4.0 – through 2.4.67 |
Weakness: CWE-122, CWE-120 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
- https://httpd.apache.org/security/vulnerabilities_24.html vendor-advisory
- http://www.openwall.com/lists/oss-security/2026/06/08/9
- https://access.redhat.com/security/cve/CVE-2026-42536 vdb-entry, x_refsource_REDHAT
- RHBZ#2486411 issue-tracking, x_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42536.json x_sadp-csaf-vex
- https://access.redhat.com/errata/RHSA-2026:56868 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:47046 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:34109 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:42828 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:67152 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:66323 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:62165 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:41906 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:25042 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:53371 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:56869 vendor-advisory, x_refsource_REDHAT