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Vulnerability record · CVE-2026-28780 · published 5 May 2026

CVE-2026-28780: Apache http server heap-based buffer overflow vulnerability

Apache · Http Server

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.

9.8 CVSS 3.1 Critical EPSS 1.6% · top 24.7% CWE-122 · Heap-based buffer overflowCWE-787 · Out-of-bounds write
9.8CVSS 3.1 base score
1.6%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
17References
14 Sep 2026Last modified by NVD

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:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://httpd.apache.org/security/vulnerabilities_24.html Release NotesVendor Advisory
http://www.openwall.com/lists/oss-security/2026/05/05/9 Mailing ListThird Party Advisory
https://access.redhat.com/errata/RHSA-2026:21391
https://access.redhat.com/errata/RHSA-2026:21433
https://access.redhat.com/errata/RHSA-2026:22140
https://access.redhat.com/errata/RHSA-2026:27200
https://access.redhat.com/errata/RHSA-2026:27201
https://access.redhat.com/errata/RHSA-2026:36373
https://access.redhat.com/errata/RHSA-2026:36831
https://access.redhat.com/errata/RHSA-2026:36846
https://access.redhat.com/errata/RHSA-2026:47046
https://access.redhat.com/errata/RHSA-2026:62165
https://access.redhat.com/errata/RHSA-2026:66323
https://access.redhat.com/errata/RHSA-2026:67152
https://access.redhat.com/security/cve/CVE-2026-28780
https://bugzilla.redhat.com/show_bug.cgi?id=2466913
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-28780.json

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-28780), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.