CVE-2026-28780

Modified Modified - Updated After Analysis

Heap-based Buffer Overflow in Apache HTTP Server mod_proxy_ajp

Publication date: 2026-05-05

Last updated on: 2026-06-30

Assigner: Apache Software Foundation

Description

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.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-05-05

Last Modified

2026-06-30

Generated

2026-07-06

AI Q&A

2026-05-06

EPSS Evaluated

2026-07-05

NVD

CVE-2026-28780

EUVD

EUVD-2026-27506

Affected Vendors & Products

Vendor	Product	Version / Range
apache	http_server	to 2.4.67 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-122	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().
CWE-787	The product writes data past the end, or before the beginning, of the intended buffer.

Attack-Flow Graph

Executive Summary

This vulnerability is a heap-based buffer overflow in the mod_proxy_ajp module of the Apache HTTP Server. It occurs when mod_proxy_ajp connects to a malicious AJP server that sends a specially crafted AJP message. This message causes mod_proxy_ajp to write 4 attacker-controlled bytes beyond the end of a heap buffer, potentially leading to memory corruption.

Impact Analysis

The impact of this vulnerability is that an attacker controlling a malicious AJP server can exploit the buffer overflow to corrupt memory in the Apache HTTP Server process. This could lead to unpredictable behavior such as crashes, denial of service, or potentially arbitrary code execution depending on the environment and exploitation conditions.

Mitigation Strategies

Users are recommended to upgrade Apache HTTP Server to version 2.4.67, which fixes the heap-based buffer overflow vulnerability in mod_proxy_ajp.

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