CVE-2025-49630
Apache Http Server 2.4.26 – 2.4.64
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HSummary
CVE-2025-49630 is a high-severity Reachable Assertion (CWE-617) vulnerability in Apache Http Server. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked in the top 36% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-8 (Security and Privacy Engineering Principles) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2025-49630 is a reachable assertion vulnerability (CWE-617) in Apache HTTP Server versions 2.4.26 through 2.4.63 that affects the mod_proxy_http2 module. It is triggered only in reverse-proxy configurations that use an HTTP/2 backend and have ProxyPreserveHost set to "on", allowing an unauthenticated remote client to cause the server process to abort.
An attacker with network access can send specially crafted requests to the affected proxy, resulting in a denial of service that impacts availability but does not allow code execution or data disclosure. The CVSS 3.1 score of 7.5 reflects the low attack complexity and lack of required privileges or user interaction.
Advisories published on the Apache HTTP Server security page and mirrored on oss-security and Debian LTS lists recommend upgrading to a fixed release or applying vendor patches; they also note that disabling ProxyPreserveHost or avoiding HTTP/2 backends mitigates the issue when an immediate update is not feasible.
The EPSS score rose from a low baseline to a recorded peak of 0.0467 before settling at the current value of 0.0267, indicating measurable post-disclosure interest in exploitation.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-21017
Vulnerability Data
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…
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backend, with ProxyPreserveHost set to "on".
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation finds reachable assertions during development.
Security engineering principles discourage use of assertions for handling untrusted input.
Validating untrusted inputs structurally prevents attacker data from reaching and triggering assertions.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly prevent unsafe assertions from being coded in reachable paths.
Runtime monitoring of software can detect assertion-triggered crashes as adverse events.
Vulnerability identification processes can discover and record reachable-assertion flaws before deployment.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development can detect reachable assertions before release, reducing the likelihood of exploitation.
Secure development lifecycle mandates defensive coding and input validation that prevent reachable assertions from being triggered by untrusted data.
Application security requirements can specify that assertions must not be reachable from attacker-controlled inputs.
Secure architecture principles discourage the use of assertions for runtime error handling that an attacker could exploit.
Secure coding standards explicitly ban the use of assert() or equivalent statements that can be triggered by external input.