Vulnerability · Published May 4, 2026 · Assigned by apache
CVE-2026-33857Apache HTTP Server: Off-by-one OOB reads in AJP getter functions
Medium 5.3
In plain English
A medium-severity out-of-bounds read 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 0.4% (higher than 34% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)5.3Medium
Exploit odds (30 days)0.4%top 66.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Out-of-bounds Read vulnerability in mod_proxy_ajp of Apache HTTP Server. This issue affects Apache HTTP Server: through 2.4.66. Users are recommended to upgrade to version 2.4.67, which fixes the issue.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | httpd | 2.4.63-13.el10_2.1 | ALSA-2026:21433 |
| AlmaLinux:8 | httpd | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 | ALSA-2026:22140 |
| AlmaLinux:9 | httpd | 2.4.62-13.el9_8.1 | ALSA-2026:21391 |
| AlmaLinux:10 | httpd-core | 2.4.63-13.el10_2.1 | ALSA-2026:21433 |
| AlmaLinux:9 | httpd-core | 2.4.62-13.el9_8.1 | ALSA-2026:21391 |
| AlmaLinux:10 | httpd-devel | 2.4.63-13.el10_2.1 | ALSA-2026:21433 |
| AlmaLinux:8 | httpd-devel | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 | ALSA-2026:22140 |
| AlmaLinux:9 | httpd-devel | 2.4.62-13.el9_8.1 | ALSA-2026:21391 |
| AlmaLinux:10 | httpd-filesystem | 2.4.63-13.el10_2.1 | ALSA-2026:21433 |
| AlmaLinux:8 | httpd-filesystem | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 | ALSA-2026:22140 |
| AlmaLinux:9 | httpd-filesystem | 2.4.62-13.el9_8.1 | ALSA-2026:21391 |
| AlmaLinux:10 | httpd-manual | 2.4.63-13.el10_2.1 | ALSA-2026:21433 |
| AlmaLinux:8 | httpd-manual | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 | ALSA-2026:22140 |
| AlmaLinux:9 | httpd-manual | 2.4.62-13.el9_8.1 | ALSA-2026:21391 |
| AlmaLinux:10 | httpd-tools | 2.4.63-13.el10_2.1 | ALSA-2026:21433 |
| AlmaLinux:8 | httpd-tools | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 | ALSA-2026:22140 |
| AlmaLinux:9 | httpd-tools | 2.4.62-13.el9_8.1 | ALSA-2026:21391 |
| AlmaLinux:8 | mod_http2 | 1.15.7-10.module_el8.10.0+4185+0955a0d7.5 | ALSA-2026:22140 |
| AlmaLinux:10 | mod_ldap | 2.4.63-13.el10_2.1 | ALSA-2026:21433 |
| AlmaLinux:8 | mod_ldap | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 | ALSA-2026:22140 |
| AlmaLinux:9 | mod_ldap | 2.4.62-13.el9_8.1 | ALSA-2026:21391 |
| AlmaLinux:10 | mod_lua | 2.4.63-13.el10_2.1 | ALSA-2026:21433 |
| AlmaLinux:9 | mod_lua | 2.4.62-13.el9_8.1 | ALSA-2026:21391 |
| AlmaLinux:8 | mod_md | 1:2.0.8-8.module_el8.10.0+4088+57f011c1.2 | ALSA-2026:22140 |
| AlmaLinux:10 | mod_proxy_html | 1:2.4.63-13.el10_2.1 | ALSA-2026:21433 |
| AlmaLinux:8 | mod_proxy_html | 1:2.4.37-65.module_el8.10.0+4185+0955a0d7.8 | ALSA-2026:22140 |
| AlmaLinux:9 | mod_proxy_html | 1:2.4.62-13.el9_8.1 | ALSA-2026:21391 |
| AlmaLinux:10 | mod_session | 2.4.63-13.el10_2.1 | ALSA-2026:21433 |
| AlmaLinux:8 | mod_session | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 | ALSA-2026:22140 |
| AlmaLinux:9 | mod_session | 2.4.62-13.el9_8.1 | ALSA-2026:21391 |
| AlmaLinux:10 | mod_ssl | 1:2.4.63-13.el10_2.1 | ALSA-2026:21433 |
| AlmaLinux:8 | mod_ssl | 1:2.4.37-65.module_el8.10.0+4185+0955a0d7.8 | ALSA-2026:22140 |
| AlmaLinux:9 | mod_ssl | 1:2.4.62-13.el9_8.1 | ALSA-2026:21391 |
| Alpine:v3.20 | apache2 | 2.4.67-r0 | ALPINE-CVE-2026-33857 |
| Alpine:v3.21 | apache2 | 2.4.67-r0 | ALPINE-CVE-2026-33857 |
| Alpine:v3.22 | apache2 | 2.4.67-r0 | ALPINE-CVE-2026-33857 |
| Alpine:v3.23 | apache2 | 2.4.67-r0 | ALPINE-CVE-2026-33857 |
| Alpine:v3.24 | apache2 | 2.4.67-r0 | ALPINE-CVE-2026-33857 |
| Debian:12 | apache2 | 2.4.67-1~deb12u2 | DEBIAN-CVE-2026-33857 |
| Debian:13 | apache2 | 2.4.67-1~deb13u2 | DEBIAN-CVE-2026-33857 |
| Debian:14 | apache2 | 2.4.67-1 | DEBIAN-CVE-2026-33857 |
| Rocky Linux:10 | httpd | 0:2.4.63-13.el10_2.1 | RLSA-2026:21433 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+1830+22f0c9e0 | RLSA-2026:22140 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+2061+8d03fdec.5 | RLSA-2026:22140 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+40053+5a18018e.7 | RLSA-2026:22140 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+1840+b070a976.1 | RLSA-2026:22140 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+1842+4a9649e8.2 | RLSA-2026:22140 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+40045+6ce8579b.6 | RLSA-2026:22140 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+1984+1bed3124.4 | RLSA-2026:22140 |
| Rocky Linux:8 | httpd | 0:2.4.37-65.module+el8.10.0+1938+3b7755d4.3 | RLSA-2026:22140 |
| Rocky Linux:9 | httpd | 0:2.4.62-13.el9_8.1 | RLSA-2026:21391 |
| Rocky Linux:8 | mod_http2 | 0:1.15.7-10.module+el8.10.0+1883+38ed6c58.1 | RLSA-2026:22140 |
| Rocky Linux:8 | mod_http2 | 0:1.15.7-10.module+el8.10.0+1775+6b057638 | RLSA-2026:22140 |
| Rocky Linux:8 | mod_http2 | 0:1.15.7-10.module+el8.10.0+1830+22f0c9e0 | RLSA-2026:22140 |
| Rocky Linux:8 | mod_http2 | 0:1.15.7-10.module+el8.10.0+1938+3b7755d4.3 | RLSA-2026:22140 |
| Rocky Linux:8 | mod_http2 | 0:1.15.7-10.module+el8.10.0+2061+8d03fdec.4 | RLSA-2026:22140 |
| Rocky Linux:8 | mod_md | 1:2.0.8-8.module+el8.10.0+40053+5a18018e.2 | RLSA-2026:22140 |
| Rocky Linux:8 | mod_md | 1:2.0.8-8.module+el8.9.0+1370+89cc8ad5 | RLSA-2026:22140 |
| Ubuntu:22.04:LTS | apache2 | 2.4.52-1ubuntu4.20 | UBUNTU-CVE-2026-33857 |
| Ubuntu:24.04:LTS | apache2 | 2.4.58-1ubuntu8.12 | UBUNTU-CVE-2026-33857 |
| Ubuntu:25.10 | apache2 | 2.4.64-1ubuntu3.4 | UBUNTU-CVE-2026-33857 |
| Ubuntu:26.04:LTS | apache2 | 2.4.66-2ubuntu2.1 | UBUNTU-CVE-2026-33857 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Apache Software Foundation | Apache HTTP Server | 0 – through 2.4.66 |
Weakness: CWE-125 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N