{"id":"CVE-2026-82720","published":"2026-09-16T09:17:06.677","lastModified":"2026-09-16T19:41:10.423","description":"NLnet Labs Unbound 1.12.0 up to and including 1.26.0 has a use-after-free vulnerability when compiled for DNS-over-HTTPs support with '--with-libnghttp2'. During failure code paths (i.e., RPZ drop query, jostle due to heavy traffic), a dropped DoH stream brings down the whole DoH session and does not account properly for other DoH streams in the same session. This leads to use-after-free in those code paths. If the prerequisites are satisfied (possible RPZ drop or heavy client traffic), a malicious actor can trigger the vulnerability with a single DoH connection and the appropriate traffic. Impact is limited as the reads are not user controlled and the use-after-free leads to early returns. However, a hardened allocator can catch the use-after-free and controllably terminate the process resulting to denial of service.","cvssScore":5.9,"cvssSeverity":"MEDIUM","cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","cwes":["CWE-416"],"vendors":[],"products":[],"references":[{"url":"https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-82720.txt","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}