Apache HTTP Server mod_http DoS via Excessive Memory Allocation (2.4.17-2.4.67)
CVE-2026-49975 Published on June 8, 2026
Apache HTTP Server: mod_http2 denial of service
Memory Allocation with Excessive Size Value vulnerability in Apache HTTP Server's mod_http leads to denial of service via malicious HTTP requests.
This issue affects Apache HTTP Server: from 2.4.17 through 2.4.67.
Vulnerability Analysis
CVE-2026-49975 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. An automatable proof of concept (POC) exploit exists. 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
fixed upstream in mod_h2 https://github.com/icing/mod_h2/commit/35c6e405390ed361189a82acd96675401ea5947c 1 day later.
fixed in 2.4.x by r1934882 6 days later.
2.4.68 released 6 days later.
Weakness Type
What is a Stack Exhaustion Vulnerability?
The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.
CVE-2026-49975 has been classified to as a Stack Exhaustion vulnerability or weakness.
Products Associated with CVE-2026-49975
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Affected Versions
Apache Software Foundation Apache HTTP Server:- Version 2.4.17, <= 2.4.67 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.