CVE-2024-27316
Published: 04 April 2024
Summary
CVE-2024-27316 is a high-severity Allocation of Resources Without Limits or Throttling (CWE-770) vulnerability in Fedoraproject Fedora. Its CVSS base score is 7.5 (High).
Operationally, ranked in the top 0.5% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
Deeper analysis
CVE-2024-27316 is a denial-of-service vulnerability in the nghttp2 library that affects HTTP/2 request handling. When incoming headers exceed configured limits, nghttp2 temporarily buffers them to produce an HTTP 413 response; a client that continues sending headers without stopping causes unbounded memory growth and eventual exhaustion. The issue impacts any server or application that uses the affected nghttp2 versions, including Apache HTTP Server deployments referenced in vendor advisories.
An unauthenticated remote attacker can exploit the flaw simply by establishing an HTTP/2 connection and continuously transmitting header frames that exceed the limit. Because the vulnerability requires no authentication or user interaction and carries a CVSS availability impact of high, successful exploitation can render the target process unresponsive or crash it, resulting in service disruption.
Public advisories published by the Apache HTTP Server project, Apple, and other vendors direct administrators to apply the patched nghttp2 versions listed in their respective security bulletins. The referenced updates address the buffering behavior that leads to exhaustion.
EPSS scores for the CVE have remained elevated since disclosure, with a current value of 0.8756 and a recorded peak of 0.8941.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2024-24531
Vulnerability details
HTTP/2 incoming headers exceeding the limit are temporarily buffered in nghttp2 in order to generate an informative HTTP 413 response. If a client does not stop sending headers, this leads to memory exhaustion.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
This control implements explicit throttling on session allocation, addressing the weakness of allocating resources without limits.
Plan testing exercises resource allocation limits and throttling during simulated failures, directly addressing weaknesses that allow unbounded resource use.
Contingency plan updates ensure recovery strategies address unbounded resource allocation, making it harder for attackers to exploit lack of throttling to cause prolonged outages.
Provides continuity when unbounded resource allocation at the primary site leads to exhaustion and downtime.
Alternate services allow operations to continue when primary allocation of resources lacks limits or throttling.
Explicit planning of security-related actions requires defining limits, windows, and resource allocations, making allocation without throttling far less likely.
Measures of performance include tracking allocation behavior and throttling effectiveness, reducing the window for resource exhaustion attacks.
Imposes an inactivity-based limit on network resource allocation, throttling the number of concurrently held connections.