CVE-2026-5950

5.3 mediumEPSS 0.7%

An unbounded resend loop vulnerability exists in the BIND 9 resolver state machine during bad-server handling, enabling a remote unauthenticated attacker to cause severe resource exhaustion by sending queries that trigger specific retry conditions. This issue affects BIND 9 versions 9.18.36 through 9.18.48, 9.20.8 through 9.20.22, 9.21.7 through 9.21.21, 9.18.36-S1 through 9.18.48-S1, and 9.20.9-S1 through 9.20.22-S1.

Severity

CVSS 3.1

5.3 medium

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

EPSS: 0.7% chance of exploitation in the next 30 days; higher than 51% of CVEs (scores of 2026-10-31)
CWE: CWE-606
Published: 2026-05-20
Modified: 2026-07-23
Record from: the NVD, synced 2026-10-19

Affected

isc:bind

References

https://downloads.isc.org/isc/bind9/9.18.49
https://downloads.isc.org/isc/bind9/9.20.23
https://downloads.isc.org/isc/bind9/9.21.22
https://kb.isc.org/docs/cve-2026-5950

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