CVE-2024-28182
MediumCVSS 5.3Exploitation Probability (EPSS)
Very high risk100th percentile - higher than 100% of all known CVEs
Summary
nghttp2 is an implementation of the Hypertext Transfer Protocol version 2 in C. The nghttp2 library prior to version 1.61.0 keeps reading the unbounded number of HTTP/2 CONTINUATION frames even after a stream is reset to keep HPACK context in sync. This causes excessive CPU usage to decode HPACK stream. nghttp2 v1.61.0 mitigates this vulnerability by limiting the number of CONTINUATION frames it accepts per stream. There is no workaround for this vulnerability.
Risk Assessment
An attacker can remotely cause excessive CPU usage, leading to denial of service (DoS) on servers using nghttp2.
Recommendation
Update nghttp2 library to version 1.61.0 or later. There are no other workarounds.
Other vulnerabilities in nghttp2
See all- CVE-2015-8659Critical
Idle stream handling in nghttp2 before version 1.6.0 contains a heap-use-after-free bug that can be exploited by attackers in unspecified ways.
- CVE-2026-58055Medium
A vulnerability in nghttp2 nghttpx up to version 1.69.0 causes an HTTP/1.1 Upgrade request with a Content-Length header and body to be forwarded onto reusable keep-alive backend connections. A backend interpreting this ambiguous message in the attacker's favor enables HTTP request/response smuggling and cross-client response-queue poisoning.
- CVE-2026-24029Medium
When the early_acl_drop (earlyACLDrop in Lua) option is disabled (default is enabled) on a DNS over HTTPS frontend using the nghttp2 provider, the ACL check is skipped, allowing all clients to send DoH queries regardless of the configured ACL.
- CVE-2026-27135High
In nghttp2 library before version 1.68.1, missing internal state validation after calling `nghttp2_session_terminate_session` or `nghttp2_session_terminate_session2` causes the library to continue reading incoming data. Receiving a malformed frame can trigger an assertion failure and crash.
Original NVD description (English source)
nghttp2 is an implementation of the Hypertext Transfer Protocol version 2 in C. The nghttp2 library prior to version 1.61.0 keeps reading the unbounded number of HTTP/2 CONTINUATION frames even after a stream is reset to keep HPACK context in sync. This causes excessive CPU usage to decode HPACK stream. nghttp2 v1.61.0 mitigates this vulnerability by limiting the number of CONTINUATION frames it accepts per stream. There is no workaround for this vulnerability.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS