CVE-2026-5947 (GCVE-0-2026-5947)
Vulnerability from cvelistv5
Published
2026-05-20 13:10
Modified
2026-05-20 13:39
Severity ?
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE
  • CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
  • CWE-416 - Use After Free
Summary
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.
References
Impacted products
Vendor Product Version
ISC BIND 9 Version: 9.20.0   <
Version: 9.21.0   <
Version: 9.20.9-S1   <
Patch: 9.18.28
Patch: 9.18.28-S1
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