In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, in DNS-over-QUIC environments, with high concurrency and under pressure, an assertion in libngtcp2 about monotonic timestamps could trigger and result in server termination and thus denial of service. When interfacing with libngtcp2, for DNS-over-QUIC support in Unbound, it is expected to use monotonic time. Unbound was using realtime instead, and in DoQ environments with high concurrency and under pressure, an assert in libngtcp2 for the quic timestamp would trigger and terminate the server.This vulnerability needs Unbound to be compiled with DoQ support ('--with-libngtcp2') and the 'quic-port' to be configured for the listening interfaces.
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Fixes
Solution
This issue is fixed starting with version 1.25.2
Workaround
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References
History
Wed, 22 Jul 2026 15:30:00 +0000
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Wed, 22 Jul 2026 13:30:00 +0000
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| Description | In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, in DNS-over-QUIC environments, with high concurrency and under pressure, an assertion in libngtcp2 about monotonic timestamps could trigger and result in server termination and thus denial of service. When interfacing with libngtcp2, for DNS-over-QUIC support in Unbound, it is expected to use monotonic time. Unbound was using realtime instead, and in DoQ environments with high concurrency and under pressure, an assert in libngtcp2 for the quic timestamp would trigger and terminate the server.This vulnerability needs Unbound to be compiled with DoQ support ('--with-libngtcp2') and the 'quic-port' to be configured for the listening interfaces. | |
| Title | Assertion in libngtcp2 when under pressure in high concurrency DNS-over-QUIC environments | |
| Weaknesses | CWE-617 | |
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cvssV3_1
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Status: PUBLISHED
Assigner: NLnet Labs
Published:
Updated: 2026-07-22T14:33:23.363Z
Reserved: 2026-07-03T11:59:36.383Z
Link: CVE-2026-14586
Updated: 2026-07-22T14:33:17.415Z
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Weaknesses