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.
Published: 2026-05-05
Score: 9.8 Critical
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Debian DLA Debian DLA DLA-4571-1 [ERRATUM] [DLA 4571-1] apache2 security update
Debian DSA Debian DSA DSA-6248-1 apache2 security update
Ubuntu USN Ubuntu USN USN-8239-1 Apache HTTP Server vulnerabilities
History

Wed, 06 May 2026 20:45:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*

Wed, 06 May 2026 16:15:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}


Wed, 06 May 2026 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-787
References
Metrics threat_severity

None

cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'}

threat_severity

Important


Tue, 05 May 2026 23:30:00 +0000

Type Values Removed Values Added
References

Tue, 05 May 2026 22:45:00 +0000

Type Values Removed Values Added
First Time appeared Apache
Apache http Server
Vendors & Products Apache
Apache http Server

Tue, 05 May 2026 21:45:00 +0000

Type Values Removed Values Added
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.
Title Apache HTTP Server: buffer overflow in mod_proxy_ajp via ajp_msg_check_header()
Weaknesses CWE-122
References

Subscriptions

Apache Http Server
cve-icon MITRE

Status: PUBLISHED

Assigner: apache

Published:

Updated: 2026-05-06T15:50:18.682Z

Reserved: 2026-03-03T12:31:23.999Z

Link: CVE-2026-28780

cve-icon Vulnrichment

Updated: 2026-05-06T15:49:53.062Z

cve-icon NVD

Status : Analyzed

Published: 2026-05-05T22:16:00.390

Modified: 2026-05-06T20:31:10.843

Link: CVE-2026-28780

cve-icon Redhat

Severity : Important

Publid Date: 2026-05-05T21:29:41Z

Links: CVE-2026-28780 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-05-06T17:30:08Z

Weaknesses