CVE-2026-24029
MediumCVSS 6.5Exploitation Probability (EPSS)
Low risk5th percentile - higher than 5% of all known CVEs
Summary
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.
Risk Assessment
Unauthorized clients can use the DoH server to send DNS queries, potentially leading to data leakage or server resource abuse.
Recommendation
It is recommended to enable the early_acl_drop (or earlyACLDrop) option on the DoH frontend and ensure ACLs are properly configured and enforced.
Other vulnerabilities in nghttp2
See all- CVE-2024-28182Medium
The nghttp2 library prior to version 1.61.0 keeps reading an unbounded number of HTTP/2 CONTINUATION frames even after a stream is reset to keep the HPACK context in sync. This causes excessive CPU usage to decode HPACK state.
- 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-2026-27135High
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)
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.