CVE-2026-5947
Published: May 20, 2026
Modified: May 20, 2026
CVSS v3.1
7.5
Description
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.
| Vendor | Product | Versions |
|---|---|---|
ISC | BIND 9 | affected 9.20.0 - <= 9.20.22affected 9.21.0 - <= 9.21.21affected 9.20.9-S1 - <= 9.20.22-S1unaffected 9.18.28 - <= 9.18.49unaffected 9.18.28-S1 - <= 9.18.49-S1 |
CVSS v3.1 Details
CVSS v3.1 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability
References
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