Vulnerability · Published Oct 21, 2026 · Assigned by isc
CVE-2026-94300Concurrent GSS-TSIG messages corrupt memory
High 8.1
In plain English
A high-severity double free in BIND 9 from ISC. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.0% (higher than 62% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)8.1High
Exploit odds (30 days)1.0%top 38.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack tooling1Public PoC
Official description
Replaying GSS-TSIG signed UDP messages can result in memory corruption in "`named`". An attacker who can capture a previously signed UDP message can replay it while the negotiated TSIG key is still valid. By also sending crafted queries to a zone the attacker controls, the attacker may potentially achieve remote code execution. This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.29, 9.21.0 through 9.21.26, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.29-S1.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | bind | 32:9.18.33-15.el10_2.14 | ALSA-2026:92419 |
| AlmaLinux:8 | bind | 32:9.11.36-18.el8_10 | ALSA-2026:93925 |
| AlmaLinux:9 | bind | 32:9.16.23-40.el9_8.13 | ALSA-2026:93610 |
| AlmaLinux:10 | bind-chroot | 32:9.18.33-15.el10_2.14 | ALSA-2026:92419 |
| AlmaLinux:8 | bind-chroot | 32:9.11.36-18.el8_10 | ALSA-2026:93925 |
| AlmaLinux:9 | bind-chroot | 32:9.16.23-40.el9_8.13 | ALSA-2026:93610 |
| AlmaLinux:10 | bind-devel | 32:9.18.33-15.el10_2.14 | ALSA-2026:92419 |
| AlmaLinux:8 | bind-devel | 32:9.11.36-18.el8_10 | ALSA-2026:93925 |
| AlmaLinux:9 | bind-devel | 32:9.16.23-40.el9_8.13 | ALSA-2026:93610 |
| AlmaLinux:9 | bind-dnssec-doc | 32:9.16.23-40.el9_8.13 | ALSA-2026:93610 |
| AlmaLinux:10 | bind-dnssec-utils | 32:9.18.33-15.el10_2.14 | ALSA-2026:92419 |
| AlmaLinux:9 | bind-dnssec-utils | 32:9.16.23-40.el9_8.13 | ALSA-2026:93610 |
| AlmaLinux:10 | bind-doc | 32:9.18.33-15.el10_2.14 | ALSA-2026:92419 |
| AlmaLinux:9 | bind-doc | 32:9.16.23-40.el9_8.13 | ALSA-2026:93610 |
| AlmaLinux:8 | bind-export-devel | 32:9.11.36-18.el8_10 | ALSA-2026:93925 |
| AlmaLinux:8 | bind-export-libs | 32:9.11.36-18.el8_10 | ALSA-2026:93925 |
| AlmaLinux:10 | bind-libs | 32:9.18.33-15.el10_2.14 | ALSA-2026:92419 |
| AlmaLinux:8 | bind-libs | 32:9.11.36-18.el8_10 | ALSA-2026:93925 |
| AlmaLinux:9 | bind-libs | 32:9.16.23-40.el9_8.13 | ALSA-2026:93610 |
| AlmaLinux:8 | bind-libs-lite | 32:9.11.36-18.el8_10 | ALSA-2026:93925 |
| AlmaLinux:10 | bind-license | 32:9.18.33-15.el10_2.14 | ALSA-2026:92419 |
| AlmaLinux:8 | bind-license | 32:9.11.36-18.el8_10 | ALSA-2026:93925 |
| AlmaLinux:9 | bind-license | 32:9.16.23-40.el9_8.13 | ALSA-2026:93610 |
| AlmaLinux:8 | bind-lite-devel | 32:9.11.36-18.el8_10 | ALSA-2026:93925 |
| AlmaLinux:8 | bind-pkcs11 | 32:9.11.36-18.el8_10 | ALSA-2026:93925 |
| AlmaLinux:8 | bind-pkcs11-devel | 32:9.11.36-18.el8_10 | ALSA-2026:93925 |
| AlmaLinux:8 | bind-pkcs11-libs | 32:9.11.36-18.el8_10 | ALSA-2026:93925 |
| AlmaLinux:8 | bind-pkcs11-utils | 32:9.11.36-18.el8_10 | ALSA-2026:93925 |
| AlmaLinux:8 | bind-sdb | 32:9.11.36-18.el8_10 | ALSA-2026:93925 |
| AlmaLinux:8 | bind-sdb-chroot | 32:9.11.36-18.el8_10 | ALSA-2026:93925 |
| AlmaLinux:10 | bind-utils | 32:9.18.33-15.el10_2.14 | ALSA-2026:92419 |
| AlmaLinux:8 | bind-utils | 32:9.11.36-18.el8_10 | ALSA-2026:93925 |
| AlmaLinux:9 | bind-utils | 32:9.16.23-40.el9_8.13 | ALSA-2026:93610 |
| AlmaLinux:8 | bind9.16 | 32:9.16.23-0.22.el8_10.21 | ALSA-2026:94011 |
| AlmaLinux:8 | bind9.16-chroot | 32:9.16.23-0.22.el8_10.21 | ALSA-2026:94011 |
| AlmaLinux:8 | bind9.16-devel | 32:9.16.23-0.22.el8_10.21 | ALSA-2026:94011 |
| AlmaLinux:8 | bind9.16-dnssec-utils | 32:9.16.23-0.22.el8_10.21 | ALSA-2026:94011 |
| AlmaLinux:8 | bind9.16-doc | 32:9.16.23-0.22.el8_10.21 | ALSA-2026:94011 |
| AlmaLinux:8 | bind9.16-libs | 32:9.16.23-0.22.el8_10.21 | ALSA-2026:94011 |
| AlmaLinux:8 | bind9.16-license | 32:9.16.23-0.22.el8_10.21 | ALSA-2026:94011 |
| AlmaLinux:8 | bind9.16-utils | 32:9.16.23-0.22.el8_10.21 | ALSA-2026:94011 |
| AlmaLinux:9 | bind9.18 | 32:9.18.29-14.el9_8.12 | ALSA-2026:93072 |
| AlmaLinux:9 | bind9.18-chroot | 32:9.18.29-14.el9_8.12 | ALSA-2026:93072 |
| AlmaLinux:9 | bind9.18-devel | 32:9.18.29-14.el9_8.12 | ALSA-2026:93072 |
| AlmaLinux:9 | bind9.18-dnssec-utils | 32:9.18.29-14.el9_8.12 | ALSA-2026:93072 |
| AlmaLinux:9 | bind9.18-doc | 32:9.18.29-14.el9_8.12 | ALSA-2026:93072 |
| AlmaLinux:9 | bind9.18-libs | 32:9.18.29-14.el9_8.12 | ALSA-2026:93072 |
| AlmaLinux:9 | bind9.18-utils | 32:9.18.29-14.el9_8.12 | ALSA-2026:93072 |
| AlmaLinux:8 | python3-bind | 32:9.11.36-18.el8_10 | ALSA-2026:93925 |
| AlmaLinux:9 | python3-bind | 32:9.16.23-40.el9_8.13 | ALSA-2026:93610 |
| AlmaLinux:8 | python3-bind9.16 | 32:9.16.23-0.22.el8_10.21 | ALSA-2026:94011 |
| Alpine:v3.22 | bind | 9.20.30-r0 | ALPINE-CVE-2026-94300 |
| Alpine:v3.23 | bind | 9.20.30-r0 | ALPINE-CVE-2026-94300 |
| Alpine:v3.24 | bind | 9.20.30-r0 | ALPINE-CVE-2026-94300 |
| Debian:12 | bind9 | no fix listed | DEBIAN-CVE-2026-94300 |
| Debian:13 | bind9 | 1:9.20.30-1~deb13u1 | DEBIAN-CVE-2026-94300 |
| Debian:14 | bind9 | 1:9.20.30-1 | DEBIAN-CVE-2026-94300 |
| Rocky Linux:10 | bind | 2:9.18.33-15.el10_2.14 | RLSA-2026:92419 |
| Rocky Linux:8 | bind | 2:9.11.36-18.el8_10 | RLSA-2026:93925 |
| Rocky Linux:9 | bind | 2:9.16.23-40.el9_8.13 | RLSA-2026:93610 |
| Rocky Linux:8 | bind9.16 | 2:9.16.23-0.22.el8_10.21 | RLSA-2026:94011 |
| Rocky Linux:9 | bind9.18 | 2:9.18.29-14.el9_8.12 | RLSA-2026:93072 |
| Ubuntu:22.04:LTS | bind9 | 1:9.18.39-0ubuntu0.22.04.8 | UBUNTU-CVE-2026-94300 |
| Ubuntu:22.04:LTS | bind9 | 1:9.18.39-0ubuntu0.22.04.8 | USN-8969-1 |
| Ubuntu:24.04:LTS | bind9 | 1:9.18.39-0ubuntu0.24.04.9 | UBUNTU-CVE-2026-94300 |
| Ubuntu:24.04:LTS | bind9 | 1:9.18.39-0ubuntu0.24.04.9 | USN-8969-1 |
| Ubuntu:26.04:LTS | bind9 | 1:9.20.24-1ubuntu0.5 | USN-8969-1 |
| Ubuntu:26.04:LTS | bind9 | 1:9.20.24-1ubuntu0.5 | UBUNTU-CVE-2026-94300 |
| Ubuntu:26.10 | bind9 | 1:9.20.24-1ubuntu3.1 | USN-8969-1 |
| Ubuntu:26.10 | bind9 | 1:9.20.24-1ubuntu3.1 | UBUNTU-CVE-2026-94300 |
| Ubuntu:22.04:LTS | bind9-libs | no fix listed | UBUNTU-CVE-2026-94300 |
| Ubuntu:24.04:LTS | isc-dhcp | no fix listed | UBUNTU-CVE-2026-94300 |
| Ubuntu:26.04:LTS | isc-dhcp | no fix listed | UBUNTU-CVE-2026-94300 |
Affected products (as reported)
Weakness: CWE-415, CWE-362 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- CVE-2026-94300 vendor-advisory
- https://downloads.isc.org/isc/bind9/9.20.30 patch
- https://downloads.isc.org/isc/bind9/9.21.27 patch