CVE-2026-28780

Heap-based Buffer Overflow vulnerability in mod_proxy_ajp of Apache HTTP Server. If mod_proxy_ajp connects to a malicious AJP server this AJP server can send a malicious AJP message back to mod_proxy_ajp and cause it to write 4 attacker controlled bytes after the end of a heap based buffer.

This issue affects Apache HTTP Server: through 2.4.66.

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

Weakness

A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

Affected Software

Name	Vendor	Start Version	End Version
Http_server	Apache	*	2.4.67 (excluding)
JBoss Core Services for RHEL 8	RedHat	jbcs-httpd24-httpd-0:2.4.62-13.el8jbcs	*
JBoss Core Services on RHEL 7	RedHat	jbcs-httpd24-httpd-0:2.4.62-13.el7jbcs	*
Red Hat Enterprise Linux 10	RedHat	httpd-0:2.4.63-13.el10_2.1	*
Red Hat Enterprise Linux 8	RedHat	httpd:2.4-8100020260519200905.489197e6	*
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support	RedHat	httpd:2.4-8040020260702193120.522a0ee4	*
Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On	RedHat	httpd:2.4-8040020260702193120.522a0ee4	*
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support	RedHat	httpd:2.4-8060020260702195216.ad008a3a	*
Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On	RedHat	httpd:2.4-8060020260702195216.ad008a3a	*
Red Hat Enterprise Linux 8.8 Telecommunications Update Service	RedHat	httpd:2.4-8080020260702200145.63b34585	*
Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions	RedHat	httpd:2.4-8080020260702200145.63b34585	*
Red Hat Enterprise Linux 9	RedHat	httpd-0:2.4.62-13.el9_8.1	*
Red Hat JBoss Core Services 2.4.62.SP4	RedHat	httpd	*
Apache2	Ubuntu	devel	*
Apache2	Ubuntu	esm-infra-legacy/trusty	*
Apache2	Ubuntu	esm-infra-legacy/xenial	*
Apache2	Ubuntu	esm-infra/bionic	*
Apache2	Ubuntu	esm-infra/focal	*
Apache2	Ubuntu	esm-infra/xenial	*
Apache2	Ubuntu	jammy	*
Apache2	Ubuntu	noble	*
Apache2	Ubuntu	questing	*
Apache2	Ubuntu	resolute	*
Apache2	Ubuntu	upstream	*

Potential Mitigations

Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking.
D3-SFCV (Stack Frame Canary Validation) from D3FEND [REF-1334] discusses canary-based detection in detail.
Run or compile the software using features or extensions that randomly arrange the positions of a program’s executable and libraries in memory. Because this makes the addresses unpredictable, it can prevent an attacker from reliably jumping to exploitable code.
Examples include Address Space Layout Randomization (ASLR) [REF-58] [REF-60] and Position-Independent Executables (PIE) [REF-64]. Imported modules may be similarly realigned if their default memory addresses conflict with other modules, in a process known as “rebasing” (for Windows) and “prelinking” (for Linux) [REF-1332] using randomly generated addresses. ASLR for libraries cannot be used in conjunction with prelink since it would require relocating the libraries at run-time, defeating the whole purpose of prelinking.
For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].

https://cwe.mitre.org/data/definitions/92.html

NVD	https://nvd.nist.gov/vuln/detail/CVE-2026-28780
CWE	https://cwe.mitre.org/data/definitions/122.html

Heap-based Buffer Overflow

Weakness

Affected Software

Potential Mitigations

Related Attack Patterns

References