Apache HTTP Server Memory Leak before 2.4.64 (CVE-2025-53020)
CVE-2025-53020 Published on July 10, 2025
Apache HTTP Server: HTTP/2 DoS by Memory Increase
Late Release of Memory after Effective Lifetime vulnerability in Apache HTTP Server.
This issue affects Apache HTTP Server: from 2.4.17 up to 2.4.63.
Users are recommended to upgrade to version 2.4.64, which fixes the issue.
Vulnerability Analysis
CVE-2025-53020 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Timeline
reported
fix developed 1 day later.
2.4.x revision 1927046 18 days later.
Weakness Type
What is a Memory Leak Vulnerability?
The software does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory. This is often triggered by improper handling of malformed data or unexpectedly interrupted sessions. In some languages, developers are responsible for tracking memory allocation and releasing the memory. If there are no more pointers or references to the memory, then it can no longer be tracked and identified for release.
CVE-2025-53020 has been classified to as a Memory Leak vulnerability or weakness.
Products Associated with CVE-2025-53020
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Affected Versions
Apache Software Foundation Apache HTTP Server:- Version 2.4.17, <= 2.4.63 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.