Answer in brief
CVE-2026-28780 records a Critical severity (CVSS 9.8) vulnerability in Apache HTTP Server: buffer overflow in mod_proxy_ajp via ajp_msg_check_header(). The current sources do not mark it as known exploited. The current feed maps Apache Software Foundation/Apache HTTP Server (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
Answer in brief
CVE-2026-28780 records a Critical severity (CVSS 9.8) vulnerability in Apache HTTP Server: buffer overflow in mod_proxy_ajp via ajp_msg_check_header(). The current sources do not mark it as known exploited. The current feed maps Apache Software Foundation/Apache HTTP Server (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 9.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Apache Software Foundation/Apache HTTP Server (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Apache Software Foundation/Apache HTTP Servergeneric | 0 | Not reported |
Published upstream
May 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 28, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 8, 2026
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.
Quoted source text, attributed separately from HOL analysis.
CVSS is 9.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Apache Software Foundation/Apache HTTP Server (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Apache Software Foundation/Apache HTTP Servergeneric | 0 | Not reported |
Published upstream
May 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 28, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 8, 2026
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.
Quoted source text, attributed separately from HOL analysis.