| Name | CVE-2026-5950 |
| Description | An unbounded resend loop vulnerability exists in the BIND 9 resolver state machine during bad-server handling, enabling a remote unauthenticated attacker to cause severe resource exhaustion by sending queries that trigger specific retry conditions. This issue affects BIND 9 versions 9.18.36 through 9.18.48, 9.20.8 through 9.20.22, 9.21.7 through 9.21.21, 9.18.36-S1 through 9.18.48-S1, and 9.20.9-S1 through 9.20.22-S1. |
| Source | CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
| References | DSA-6285-1 |
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|---|---|---|
| bind9 (PTS) | bullseye | 1:9.16.50-1~deb11u2 | vulnerable |
| bullseye (security) | 1:9.16.50-1~deb11u5 | vulnerable | |
| bookworm | 1:9.18.47-1~deb12u1 | vulnerable | |
| bookworm (security) | 1:9.18.49-1~deb12u1 | fixed | |
| trixie | 1:9.20.21-1~deb13u1 | vulnerable | |
| trixie (security) | 1:9.20.23-1~deb13u1 | fixed | |
| forky, sid | 1:9.20.24-1 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|---|---|---|---|---|---|
| bind9 | source | bookworm | 1:9.18.49-1~deb12u1 | DSA-6285-1 | ||
| bind9 | source | trixie | 1:9.20.23-1~deb13u1 | DSA-6285-1 | ||
| bind9 | source | (unstable) | 1:9.20.23-1 |
https://kb.isc.org/docs/cve-2026-5950
https://gitlab.isc.org/isc-projects/bind9/-/commit/1c390aacaedaf788a04ba053758c1b7f53673f0b (v9.20.23)
https://gitlab.isc.org/isc-projects/bind9/-/commit/379ca10cf34759d0c007cebcd9280911161bca1a (9.16-branch)