CVE-2025-49630
Description
An assertion failure flaw was found in Apache httpd. Untrusted clients can send inputs that trigger an assertion failure in the mod_proxy_http2 module, which likely results in an Apache HTTP server crash or denial of service (DoS).
Statement
The vulnerability only affects Appache httpd if a reverse proxy is configured for an HTTP/2 backend, with the ProxyPreserveHost set to "on".
This vulnerability is rated as Moderate because it requires a highly specific and non-default configuration to be exploitable—namely, an Apache HTTP Server acting as a reverse proxy with an HTTP/2 backend and ProxyPreserveHost set to "on". The flaw results in an assertion failure in the mod_proxy_http2 module when handling specially crafted inputs from untrusted clients. While this can lead to a denial of service via server crash, the impact is limited to availability, with no risk of remote code execution or data leakage. Additionally, the condition is recoverable through a simple restart, and there is no persistent state corruption.
Mitigation
No mitigation is currently available that meets Red Hat Product Security’s standards for usability, deployment, applicability, or stability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | N/A | 7.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An attacker that can trigger an assert statement can still lead to a denial of service if the relevant code can be triggered by an attacker, and if the scope of the assert() extends beyond the attacker's own session.
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