CVE-2026-19033

Publication date 16 September 2026

Last updated 14 October 2026

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

6.5 · Medium

Score breakdown

Description

For a secondary zone with transfers restricted by TSIG, `named` may start to serve the data provided in a zone transfer before the final message with the TSIG signature arrives. This could allow an attacker that does not actually possess a valid TSIG signature to send unauthorized zone contents to a secondary server. Although no TSIG signature ever arrives, `named` does not rollback to the pre-transfer state. To exploit the vulnerability, the transfer must be a multi-message TCP IXFR, as described by RFC 8945. This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.27-S1.

Read the notes from the security team

Status

Package Ubuntu Release Status
bind9 26.04 LTS resolute
Fixed 1:9.20.24-1ubuntu0.4
24.04 LTS noble
Fixed 1:9.18.39-0ubuntu0.24.04.8
22.04 LTS jammy
Fixed 1:9.18.39-0ubuntu0.22.04.7
20.04 LTS focal
Fixed 1:9.18.30-0ubuntu0.20.04.2+esm3
18.04 LTS bionic
Fixed 1:9.11.3+dfsg-1ubuntu1.19+esm6
16.04 LTS xenial
Fixed 1:9.10.3.dfsg.P4-8ubuntu1.19+esm11
14.04 LTS trusty
Fixed 1:9.9.5.dfsg-3ubuntu0.19+esm15
isc-dhcp 26.04 LTS resolute
Needs evaluation
24.04 LTS noble
Needs evaluation
22.04 LTS jammy
Not affected
20.04 LTS focal
Not affected
18.04 LTS bionic
Needs evaluation
16.04 LTS xenial
Not affected
14.04 LTS trusty
Not affected
bind9-libs 26.04 LTS resolute Not in release
24.04 LTS noble Not in release
22.04 LTS jammy
Needs evaluation
20.04 LTS focal
Needs evaluation

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Notes

alexmurray

As of isc-dhcp-4.4.3-1, isc-dhcp vendors bind9 libs

mdeslaur

in focal and jammy, isc-dhcp uses the bind9-libs package

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
bind9

Severity score breakdown

CVSS version: CVSS v3.0

Base score 6.5 · Medium

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:L

References

Related Ubuntu Security Notices (USN)

Other references

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