CVE-2026-44690 (High) detected in multiple libraries

[mend-bolt-for-github]

CVE-2026-44690 - High Severity Vulnerability

Vulnerable Libraries - src4.0.4, src4.0.4, src4.0.4, src4.0.4, src4.0.4

src4.0.4

Library home page: https://github.com/MidnightBSD/src.git

Vulnerable Source Files (5)

/contrib/unbound/validator/validator.c
/contrib/unbound/services/cache/rrset.c
/contrib/unbound/validator/val_sigcrypt.c
/contrib/unbound/validator/val_utils.h
/contrib/unbound/validator/val_utils.c

src4.0.4

Library home page: https://github.com/MidnightBSD/src.git

Vulnerable Source Files (5)

/contrib/unbound/validator/validator.c
/contrib/unbound/services/cache/rrset.c
/contrib/unbound/validator/val_sigcrypt.c
/contrib/unbound/validator/val_utils.h
/contrib/unbound/validator/val_utils.c

src4.0.4

Library home page: https://github.com/MidnightBSD/src.git

Vulnerable Source Files (5)

/contrib/unbound/validator/validator.c
/contrib/unbound/services/cache/rrset.c
/contrib/unbound/validator/val_sigcrypt.c
/contrib/unbound/validator/val_utils.h
/contrib/unbound/validator/val_utils.c

src4.0.4

Library home page: https://github.com/MidnightBSD/src.git

Vulnerable Source Files (5)

/contrib/unbound/validator/validator.c
/contrib/unbound/services/cache/rrset.c
/contrib/unbound/validator/val_sigcrypt.c
/contrib/unbound/validator/val_utils.h
/contrib/unbound/validator/val_utils.c

src4.0.4

Library home page: https://github.com/MidnightBSD/src.git

Vulnerable Source Files (5)

/contrib/unbound/validator/validator.c
/contrib/unbound/services/cache/rrset.c
/contrib/unbound/validator/val_sigcrypt.c
/contrib/unbound/validator/val_utils.h
/contrib/unbound/validator/val_utils.c

Found in base branches: stable/4.0, master

Vulnerability Details

In NLnet Labs Unbound 1.7.0 up to and including 1.25.1, insufficient validation of the RRSIG.Labels field combined with premature cache writes during RFC 8198 aggressive NSEC processing leads to cache poisoning that permits a malicious actor controlling a single delegated zone to poison arbitrary sibling zones under NSEC-signed parent domains. A malicious actor with one registered domain under an NSEC-signed TLD can serve malicious insecure DNS responses for unrelated sibling domains (sharing the same parent zone). Arbitrary delegations that do not exist under the parent domain and are covered by the parent's NSEC chain can be brought into insecure existence by fraudulent wildcard DS records (less labels than expected, unknown algorithm) from the malicious sibling domain. This allows the malicious actor to inject insecure wildcard records for those delegations.

Publish Date: 2026-07-22

URL: CVE-2026-44690

CVSS 3 Score Details (7.5)

Base Score Metrics:

• Exploitability Metrics:
  • Attack Vector: Network
  • Attack Complexity: Low
  • Privileges Required: None
  • User Interaction: None
  • Scope: Unchanged
• Impact Metrics:
  • Confidentiality Impact: None
  • Integrity Impact: High
  • Availability Impact: None

For more information on CVSS3 Scores, click here.

Suggested Fix

Type: Upgrade version

Release Date: 2026-07-22

Fix Resolution: https://github.com/NLnetLabs/unbound.git - release-1.25.2

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