CVE-2026-5950
Unbounded resend loop in BIND 9 resolver
CVE-2026-5950 is fixed in 20 products on 1 platform, first by bind9 1:9.20.18-1ubuntu2.1, released May 19, 2026. It is not reported as exploited. Patch Radar priority: Routine.
Routine
CVSS
5.3
Moderate
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0066
51st percentile
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.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| bind · amzn 2023 | 32:9.18.49-1.amzn2023.0.1 | ALAS2023-2026-1755 | May 25, 2026 |
| bind · opensuse-leap 16.0 | 9.20.23-160000.1.1 | OPENSUSE-SU-2026:21123-1 | Jun 20, 2026 |
| bind · sles 15.6 | 9.18.49-150600.3.26.1 | SUSE-SU-2026:2676-1 | Jun 29, 2026 |
| bind · sles 15.7 | 9.20.23-150700.3.25.1 | SUSE-SU-2026:2673-1 | Jul 2, 2026 |
| bind · sles 16.0 | 9.20.23-160000.1.1 | SUSE-SU-2026:22198-1 | Jun 20, 2026 |
| bind-chroot · amzn 2023 | 32:9.18.49-1.amzn2023.0.1 | ALAS2023-2026-1755 | May 25, 2026 |
| bind-debuginfo · amzn 2023 | 32:9.18.49-1.amzn2023.0.1 | ALAS2023-2026-1755 | May 25, 2026 |
| bind-debugsource · amzn 2023 | 32:9.18.49-1.amzn2023.0.1 | ALAS2023-2026-1755 | May 25, 2026 |
| bind-devel · amzn 2023 | 32:9.18.49-1.amzn2023.0.1 | ALAS2023-2026-1755 | May 25, 2026 |
| bind-dnssec-utils · amzn 2023 | 32:9.18.49-1.amzn2023.0.1 | ALAS2023-2026-1755 | May 25, 2026 |
| bind-dnssec-utils-debuginfo · amzn 2023 | 32:9.18.49-1.amzn2023.0.1 | ALAS2023-2026-1755 | May 25, 2026 |
| bind-doc · amzn 2023 | 32:9.18.49-1.amzn2023.0.1 | ALAS2023-2026-1755 | May 25, 2026 |
| bind-libs · amzn 2023 | 32:9.18.49-1.amzn2023.0.1 | ALAS2023-2026-1755 | May 25, 2026 |
| bind-libs-debuginfo · amzn 2023 | 32:9.18.49-1.amzn2023.0.1 | ALAS2023-2026-1755 | May 25, 2026 |
| bind-license · amzn 2023 | 32:9.18.49-1.amzn2023.0.1 | ALAS2023-2026-1755 | May 25, 2026 |
| bind-utils · amzn 2023 | 32:9.18.49-1.amzn2023.0.1 | ALAS2023-2026-1755 | May 25, 2026 |
| bind-utils-debuginfo · amzn 2023 | 32:9.18.49-1.amzn2023.0.1 | ALAS2023-2026-1755 | May 25, 2026 |
| bind9 · Debian 12.15 (bookworm) | 1:9.18.49-1~deb12u2 | DEBIAN-CVE-2026-5950 | May 27, 2026 |
| bind9 · Debian 13.5 (trixie) | 1:9.20.23-1~deb13u1 | DEBIAN-CVE-2026-5950 | May 27, 2026 |
| bind9 · Debian 14 | 1:9.20.23-1 | DEBIAN-CVE-2026-5950 | May 27, 2026 |
| bind9 · Ubuntu 22.04.1 LTS (jammy) | 1:9.18.39-0ubuntu0.22.04.4 | bind9 1:9.18.39-0ubuntu0.22.04.4 | May 27, 2026 |
| bind9 · Ubuntu 24.04.5 LTS (noble) | 1:9.18.39-0ubuntu0.24.04.5 | bind9 1:9.18.39-0ubuntu0.24.04.5 | May 27, 2026 |
| bind9 · Ubuntu 25.10 (questing) | 1:9.20.11-1ubuntu2.4 | bind9 1:9.20.11-1ubuntu2.4 | May 27, 2026 |
| bind9 · Ubuntu 26.04.1 LTS (resolute) | 1:9.20.18-1ubuntu2.1 | bind9 1:9.20.18-1ubuntu2.1 | May 19, 2026 |
| bind9-dnsutils · Ubuntu 22.04.1 LTS (jammy) | 1:9.18.39-0ubuntu0.22.04.4 | bind9-dnsutils 1:9.18.39-0ubuntu0.22.04.4 | May 27, 2026 |
| bind9-dnsutils · Ubuntu 24.04.5 LTS (noble) | 1:9.18.39-0ubuntu0.24.04.5 | bind9-dnsutils 1:9.18.39-0ubuntu0.24.04.5 | May 27, 2026 |
| bind9-dnsutils · Ubuntu 25.10 (questing) | 1:9.20.11-1ubuntu2.4 | bind9-dnsutils 1:9.20.11-1ubuntu2.4 | May 27, 2026 |
| bind9-dnsutils · Ubuntu 26.04.1 LTS (resolute) | 1:9.20.18-1ubuntu2.1 | bind9-dnsutils 1:9.20.18-1ubuntu2.1 | May 19, 2026 |
| bind9-host · Ubuntu 22.04.1 LTS (jammy) | 1:9.18.39-0ubuntu0.22.04.4 | bind9-host 1:9.18.39-0ubuntu0.22.04.4 | May 27, 2026 |
| bind9-host · Ubuntu 24.04.5 LTS (noble) | 1:9.18.39-0ubuntu0.24.04.5 | bind9-host 1:9.18.39-0ubuntu0.24.04.5 | May 27, 2026 |
| bind9-host · Ubuntu 25.10 (questing) | 1:9.20.11-1ubuntu2.4 | bind9-host 1:9.20.11-1ubuntu2.4 | May 27, 2026 |
| bind9-host · Ubuntu 26.04.1 LTS (resolute) | 1:9.20.18-1ubuntu2.1 | bind9-host 1:9.20.18-1ubuntu2.1 | May 19, 2026 |
| bind9-libs · Ubuntu 22.04.1 LTS (jammy) | 1:9.18.39-0ubuntu0.22.04.4 | bind9-libs 1:9.18.39-0ubuntu0.22.04.4 | May 27, 2026 |
| bind9-libs · Ubuntu 24.04.5 LTS (noble) | 1:9.18.39-0ubuntu0.24.04.5 | bind9-libs 1:9.18.39-0ubuntu0.24.04.5 | May 27, 2026 |
| bind9-libs · Ubuntu 25.10 (questing) | 1:9.20.11-1ubuntu2.4 | bind9-libs 1:9.20.11-1ubuntu2.4 | May 27, 2026 |
| bind9-libs · Ubuntu 26.04.1 LTS (resolute) | 1:9.20.18-1ubuntu2.1 | bind9-libs 1:9.20.18-1ubuntu2.1 | May 19, 2026 |
| bind9-utils · Ubuntu 22.04.1 LTS (jammy) | 1:9.18.39-0ubuntu0.22.04.4 | bind9-utils 1:9.18.39-0ubuntu0.22.04.4 | May 27, 2026 |
| bind9-utils · Ubuntu 24.04.5 LTS (noble) | 1:9.18.39-0ubuntu0.24.04.5 | bind9-utils 1:9.18.39-0ubuntu0.24.04.5 | May 27, 2026 |
| bind9-utils · Ubuntu 25.10 (questing) | 1:9.20.11-1ubuntu2.4 | bind9-utils 1:9.20.11-1ubuntu2.4 | May 27, 2026 |
| bind9-utils · Ubuntu 26.04.1 LTS (resolute) | 1:9.20.18-1ubuntu2.1 | bind9-utils 1:9.20.18-1ubuntu2.1 | May 19, 2026 |
| bind9utils · Ubuntu 22.04.1 LTS (jammy) | 1:9.18.39-0ubuntu0.22.04.4 | bind9utils 1:9.18.39-0ubuntu0.22.04.4 | May 27, 2026 |
| bind9utils · Ubuntu 24.04.5 LTS (noble) | 1:9.18.39-0ubuntu0.24.04.5 | bind9utils 1:9.18.39-0ubuntu0.24.04.5 | May 27, 2026 |
| dnsutils · Ubuntu 22.04.1 LTS (jammy) | 1:9.18.39-0ubuntu0.22.04.4 | dnsutils 1:9.18.39-0ubuntu0.22.04.4 | May 27, 2026 |
| dnsutils · Ubuntu 24.04.5 LTS (noble) | 1:9.18.39-0ubuntu0.24.04.5 | dnsutils 1:9.18.39-0ubuntu0.24.04.5 | May 27, 2026 |
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