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1837 articles · 155771 vulns · 36/41 feeds (7d)
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7.5
CVE-2026-5946EXPLOITEDPATCHED
isc · bind

Invalid handling of CLASS != IN

Description

Multiple flaws have been identified in `named` related to the handling of DNS messages whose CLASS is not Internet (`IN`) — for example, `CHAOS` or `HESIOD`, or DNS messages that specify meta-classes (`ANY` or `NONE`) in the question section. Specially crafted requests reaching the affected code paths — recursion, dynamic updates (`UPDATE`), zone change notifications (`NOTIFY`), or processing of `IN`-specific record types in non-`IN` data — can cause assertion failures in `named`. This issue affects BIND 9 versions 9.11.0 through 9.16.50, 9.18.0 through 9.18.48, 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, 9.11.3-S1 through 9.16.50-S1, 9.18.11-S1 through 9.18.48-S1, and 9.20.9-S1 through 9.20.22-S1.

Affected Products

VendorProductVersions
iscbind9.11.0, 9.18.0, 9.20.0, 9.21.0, 9.11.3-S1, 9.18.11-S1, 9.20.9-S1

Also Affects

Downstream vendors/products affected by this vulnerability

VendorProductSourceConfidence
internet systems consortiumbindcert_advisory90%

References

  • https://kb.isc.org/docs/cve-2026-5946(vendor-advisory)
  • https://downloads.isc.org/isc/bind9/9.18.49(patch)
  • https://downloads.isc.org/isc/bind9/9.20.23(patch)
  • https://downloads.isc.org/isc/bind9/9.21.22(patch)

Related News (6 articles)

Tier A
Microsoft MSRC3d ago
CVE-2026-5946 Invalid handling of CLASS != IN
→ No new info (linked only)
Tier B
BSI Advisories5d ago
[NEU] [mittel] Internet Systems Consortium BIND: Mehrere Schwachstellen
→ No new info (linked only)
Tier B
CERT-FR5d ago
Multiples vulnérabilités dans ISC BIND (21 mai 2026)
→ No new info (linked only)
Tier B
CCCS Canada6d ago
ISC BIND security advisory (AV26-490)
→ No new info (linked only)
Tier C
oss-security6d ago
ISC has disclosed six vulnerabilities in BIND 9 (CVE-2026-3039, CVE-2026-3592, CVE-2026-3593, CVE-2026-5946, CVE-2026-5947, CVE-2026-5950)
→ No new info (linked only)
Tier C
VulDB6d ago
CVE-2026-5946 | ISC BIND up to 9.21.21 named recursion
→ No new info (linked only)
CVSS 3.17.5 HIGH
VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CISA KEV❌ No
Actively exploited✅ Yes
Patch available
https://kb.isc.org/docs/cve-2026-5946https://downloads.isc.org/isc/bind9/9.18.49https://downloads.isc.org/isc/bind9/9.20.23
CWECWE-20, CWE-125, CWE-617, CWE-754, CWE-843
PublishedMay 20, 2026
Last enriched6d agov2
Trending Score50
Source articles6
Independent6
Info Completeness10/14
Missing: epss, kev, iocs, mitre_attack

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MEDIUMCVE-2026-5950EXP
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Verification

State: unverified
Confidence: 0%

Vulnerability Timeline

CVE Published
May 20, 2026
Discovered by ZDM
May 20, 2026
Actively Exploited
May 20, 2026
Exploit Available
May 20, 2026
Patch Available
May 20, 2026
Updated: exploitAvailable, activelyExploited
May 20, 2026

Version History

v2
Last enriched 6d ago
v2Tier B6d ago

Updated exploit availability to true, marked as actively exploited, and set patch available to null.

exploitAvailableactivelyExploited
via CCCS Canada
v16d ago

Initial creation