CVE WatchJul 15, 2026

CVE-2026-5947

Undefined behavior may result due to a race condition leading to a use-after-free violation. If BIND receives an incoming DNS message signe

CVSS

7.5

High

EPSS

1.4%

p69

KEV

—

Exploit Today

0-100

Published: May 20, 2026 · Last modified: Jul 15, 2026 · CWE-362 · CWE-416 · CWE-367

EPSS · 30d

1.4%EPSS · 30 days1.4%

2026-06-302026-07-16

Technical 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.

Official references

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