Apache HTTP Server: mod_proxy_http2 denial of service
In certain proxy configurations, a denial of service attack against Apache HTTP Server versions 2.4.26 through to 2.4.63 can be triggered by untrusted clients causing an assertion in mod_proxy_http2. Configurations affected are a reverse proxy is configured for an HTTP/2 backend, with ProxyPreserveHost set to "on".
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describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2025-49630US | — | — | ||
In certain proxy configurations, a denial of service attack against Apache HTTP Server versions 2.4.26 through to 2.4.63 can be triggered by untrusted clients causing an assertion… | ||||
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references
External citations — patches, advisories, analysis.
- http://www.openwall.com/lists/oss-security/2025/07/10/2WEB
- http://www.openwall.com/lists/oss-security/2025/07/10/7WEB
- https://httpd.apache.org/security/vulnerabilities_24.htmlADVISORY
- https://lists.debian.org/debian-lts-announce/2025/08/msg00009.htmlWEB
- https://nvd.nist.gov/vuln/detail/CVE-2025-49630WEB
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