CVE-2026-41637
Is CVE-2026-41637 real, exploitable, or a false positive? Here's the community verdict.
signals
public sources
Moderate signals. Triage by your actual exposure and reachability.
baseline read
auto · not a community verdict
Low signal — verdict needed
Few public signals point to active risk. Whether a scanner hit here is a true or false positive depends on your version and config — community verdicts decide.
Based on CVSS
Confirm or dispute →CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, client terminated DNS-over-QUIC (DoQ) queries are not accounted properly by Unbound resulting in low-cost inflation of the waiting number of replies for already in-flight resolution queries. This results in degradation of resolution service for new clients for already in-flight queries. A malicious actor can exploit the vulnerability by issuing DoQ queries for query names that need resolution and proceeding on immediately terminating the query by one of STOP_SENDING/RESET_STREAM/CONNECTION_CLOSE QUIC frames. Those terminated DoQ queries are not properly counted for and keep inflating the number of waiting replies for in-flight queries. When the maximum is reached, it results in silent query drops for new clients needing resolution for already in-flight queries. This vulnerability needs Unbound to be compiled with DoQ support ('--with-libngtcp2') and the 'quic-port' to be configured for the listening interfaces. Additionally, a malicious actor needs access to multiple source IPs to bypass the by-default configured 'wait-limit' option.
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Same weakness: CWE-772.
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