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.
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.
Metrics
Affected Vendors & Products
Advisories
No advisories yet.
Fixes
Solution
Upgrade to the patched release most closely related to your current version of BIND 9: 9.20.29, 9.21.26, or 9.20.29-S1.
Workaround
No workarounds known.
References
History
Wed, 16 Sep 2026 14:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | Unauthenticated IXFR deltas are applied to the live zone before TSIG verification | |
| First Time appeared |
Isc
Isc bind |
|
| Weaknesses | CWE-349 | |
| CPEs | cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Isc
Isc bind |
|
| References |
| |
| Metrics |
cvssV3_1
|
Projects
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Status: PUBLISHED
Assigner: isc
Published:
Updated: 2026-09-16T14:10:08.535Z
Reserved: 2026-08-06T04:18:09.842Z
Link: CVE-2026-19033
No data.
Status : Awaiting Analysis
Published: 2026-09-16T15:17:33.393
Modified: 2026-09-16T19:27:00.080
Link: CVE-2026-19033
No data.
OpenCVE Enrichment
No data.
Weaknesses