6.5 MEDIUM
- CVSS version (CVSS): 3.1
- Attack Vector (AV): Network (N)
- Attack Complexity (AC): High (H)
- Privileges Required (PR): None (N)
- User Interaction (UI): None (N)
- Scope (S): Unchanged (U)
- Confidentiality (C): None (N)
- Integrity (I): High (H)
- Availability (A): Low (L)
- Modified Attack Vector (MAV): Network (N)
- Modified Attack Complexity (MAC): High (H)
- Modified Privileges Required (MPR): None (N)
- Modified User Interaction (MUI): None (N)
- Modified Confidentiality (MC): None (N)
- Modified Scope (MS): Unchanged (U)
- Modified Integrity (MI): High (H)
- Modified Availability (MA): Low (L)
Activity log
- Created & dismissed (no matching packages found) suggestion
Unauthenticated IXFR deltas are applied to the live zone before TSIG verification
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.
References
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CVE-2026-19033 vendor-advisory
Affected products
- =<9.21.25
- =<9.18.50-S1
- =<9.20.27-S1
- =<9.20.27
- =<9.18.50