CVE-2026-5947
HIGH
7,5
Source: [email protected]
Attack Vector: network
Attack Complexity: low
Privileges Required: none
User Interaction: none
Scope: unchanged
Confidentiality: none
Integrity: none
Availability: high
Description
AI Translation Available
Undefined behavior may result due to a race condition leading to a use-after-free violation. If BIND receives an incoming DNS message signed with SIG(0), it begins work to validate that signature. If, during that validation, the 'recursive-clients' limit is reached (as would occur during a query flood), and that same DNS message is discarded per the limit, there is a brief window of time while the SIG(0) validation may attempt to read the now-discarded DNS message.
This issue affects BIND 9 versions 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, and 9.20.9-S1 through 9.20.22-S1.
BIND 9 versions 9.18.28 through 9.18.49 and 9.18.28-S1 through 9.18.49-S1 are NOT affected.
362
Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
DraftCommon Consequences
Security Scopes Affected:
Availability
Confidentiality
Integrity
Access Control
Potential Impacts:
Dos: Resource Consumption (Cpu)
Dos: Resource Consumption (Memory)
Dos: Resource Consumption (Other)
Dos: Crash, Exit, Or Restart
Dos: Instability
Read Files Or Directories
Read Application Data
Execute Unauthorized Code Or Commands
Gain Privileges Or Assume Identity
Bypass Protection Mechanism
Applicable Platforms
Languages:
C, C++, Java
Technologies:
Mobile, ICS/OT
416
Use After Free
StableCommon Consequences
Security Scopes Affected:
Integrity
Availability
Confidentiality
Potential Impacts:
Modify Memory
Dos: Crash, Exit, Or Restart
Read Memory
Execute Unauthorized Code Or Commands
Applicable Platforms
Languages:
Memory-Unsafe, C, C++
https://downloads.isc.org/isc/bind9/9.20.23
https://downloads.isc.org/isc/bind9/9.21.22
https://kb.isc.org/docs/cve-2026-5947