In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, a remote unauthenticated client can trigger a libngtcp2 assertion (if compiled with…
In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, a remote unauthenticated client can trigger a libngtcp2 assertion (if compiled with assertions on) and terminate the entire Unbound process using a single DNS-over-QUIC (DoQ) connection and one normal DNS query. This is caused by an erroneous error value passed to libngtcp2. When 'ngtcp2_conn_writev_stream()' returns 'NGTCP2_ERR_STREAM_DATA_BLOCKED', Unbound continues to call 'ngtcp2_ccerr_set_application_error()' with a '-1' error value. The 'int' literal '-1' is implicitly converted to the function's 'uint64_t error_code' parameter as
Read at NIST National Vulnerability Database (CVE API 2.0)
- Product
- dnsmasq / Unbound / PowerDNS
- CVSS
- 5.9
- Exposure class
- Edge / VPN / firewall
Why it ranks 15 (Routine)
- CVSS 5.9 medium
- Exposed product class: edge / VPN / firewall
- Recency: items published within 24 hours gain 15, within 72 hours 6, within 7 days 2.
Links
- NIST National Vulnerability Database (CVE API 2.0) (nvd.nist.gov)
- CVE-2026-55991 on this site · NVD · CVE.org · Vulnpedia
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