Bug 2535479 (CVE-2026-19033) - CVE-2026-19033 bind: BIND: Unauthorized zone content updates via unauthenticated IXFR deltas
Summary: CVE-2026-19033 bind: BIND: Unauthorized zone content updates via unauthentica...
Keywords:
Status: NEW
Alias: CVE-2026-19033
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On: 2535864
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-09-16 14:37 UTC by OSIDB Bzimport
Modified: 2026-09-17 08:49 UTC (History)
17 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-09-16 14:37:05 UTC 
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.
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