Summary
AMPHP Denial of Service via HTTP/2 CONTINUATION Frames
amphp/http will collect HTTP/2 CONTINUATION frames in an unbounded buffer and will not check the header size limit until it has received the END_HEADERS flag, resulting in an OOM crash. amphp/http-client and amphp/http-server are indirectly affected if they're used with an unpatched version of amphp/http. Early versions of amphp/http-client with HTTP/2 support (v4.0.0-rc10 to 4.0.0) are also directly affected.
Acknowledgements
Thank you to Bartek Nowotarski for reporting the vulnerability.
Impact
CVE-2024-2653 has a CVSS score of 8.2 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.1.1, 1.7.3); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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amphp/http to 2.1.1 or later; amphp/http to 1.7.3 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2024-2653? CVE-2024-2653 is a high-severity security vulnerability in amphp/http (composer), affecting versions >= 2.0.0, <= 2.1.0. It is fixed in 2.1.1, 1.7.3.
- How severe is CVE-2024-2653? CVE-2024-2653 has a CVSS score of 8.2 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which packages are affected by CVE-2024-2653?
amphp/http(composer) (versions >= 2.0.0, <= 2.1.0)amphp/http-client(composer) (versions >= 4.0.0-rc10, <= 4.0.0)
- Is there a fix for CVE-2024-2653? Yes. CVE-2024-2653 is fixed in 2.1.1, 1.7.3. Upgrade to this version or later.
- Is CVE-2024-2653 exploitable, and should I be worried? Whether CVE-2024-2653 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2024-2653 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2024-2653?
- Upgrade
amphp/httpto 2.1.1 or later - Upgrade
amphp/httpto 1.7.3 or later
- Upgrade