CVE-2026-5947
mediumpriority · track · 24EPSS 0.014 · 72 %ileDEEUUSEPSS · scored 2026-10-27
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.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 5.4–7.5
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (34)
Products and version ranges known to be affected.
advisories (1)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2026-1626Internet Systems Consortium BIND: Mehrere SchwachstellenDeutsch2026-05-20csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Internet Systems Consortium BIND ausnutzen, um eine Speicherbeschädigung auszulösen oder einen Denial-of-Service-Zustand zu verursachen.
also known as (3)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (14)
External citations — patches, advisories, analysis.
- https://access.redhat.com/security/cve/cve-2026-5947cnnvd
- https://kb.isc.org/docs/cve-2026-5947Patchcnnvd
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-5947cnnvd
- https://nvd.nist.gov/vuln/detail/CVE-2026-5947cnnvd
- https://downloads.isc.org/isc/bind9/9.20.23enisa_euvd
- https://downloads.isc.org/isc/bind9/9.21.22enisa_euvd
- https://kb.isc.org/docs/cve-2026-5947enisa_euvd
- https://access.redhat.com/errata/RHSA-2026:7412nvd
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