Vulnary
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Critical· 9.8official fix available

CVE-2026-28780

A heap-based buffer overflow exists in Apache HTTP Server's mod_proxy_ajp module. If the server connects to a malicious AJP server, the attacker can send crafted data that causes Apache to write attacker-controlled bytes beyond a heap buffer. This can lead to arbitrary code execution.

publishedMay 5, 2026
last modifiedJul 28, 2026
sourcesNVD
severity · cvss
9.8
critical · how bad it is
exploitation · epss
1%
69th percentile · chance of exploitation in 30 days
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →
auto-deletes from the system
counting…on Aug 25, 2026

An official fix is available, so this entry is kept for 30 days and then removed automatically.

01

Who is affected

Apache HTTP Server 2.4.66 and earlier, especially installations that enable mod_proxy_ajp.

02

Real-world impact

An attacker who can make the server talk to a malicious AJP server can overwrite memory, potentially taking control of the server and executing arbitrary code.

03

Why this severity

The CVSS score of 9.8 reflects that the flaw requires no authentication, can be triggered remotely, and gives an attacker full control over confidentiality, integrity, and availability.

04

What to do about it

official fix available
recommended steps
  1. 01Upgrade Apache HTTP Server to version 2.4.67 or later.
  2. 02Restart the Apache service to apply the update.

NVD-referenced vendor advisory

05

Timeline

  1. May 5, 2026 · May 5, 2026
    Published
    Disclosed and added to the National Vulnerability Database.
  2. Jul 26, 2026 · 10d ago
    Official fix available
    A vendor patch or mitigation now exists — see the remediation steps above.
  3. Jul 28, 2026 · 8d ago
    Advisory updated
    The NVD record was last revised.
06

How it’s attacked

Attack vectorNetwork (remote)
Attack complexityLow
Privileges requiredNone
User interactionNone needed
ScopeUnchanged
Confidentiality impactHigh
Integrity impactHigh
Availability impactHigh
07

References & advisories

NVD advisory ↗Search advisories ↗
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →