CVE-2026-28780
Heap-based Buffer Overflow vulnerability in mod_proxy_ajp of Apache HTTP Server.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.38%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 1.38% probability · 70th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-122, CWE-787
- Affected
- apache/http server
- Source
- security@apache.org
References
- https://httpd.apache.org/security/vulnerabilities_24.htmlRelease Notes, Vendor Advisory
- http://www.openwall.com/lists/oss-security/2026/05/05/9Mailing List, Third 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/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
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.