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Details of issue NIXPKGS-2026-1683

NIXPKGS-2026-1683
published on
Permalink CVE-2026-42923
6.9 MEDIUM
  • CVSS version (CVSS): 4.0
  • Attack Vector (AV): Network (N)
  • Attack Complexity (AC): Low (L)
  • Attack Requirement (AT): None (N)
  • Privileges Required (PR): None (N)
  • User Interaction (UI): None (N)
  • Vulnerable System Impact Confidentiality (VC): None (N)
  • Vulnerable System Impact Integrity (VI): None (N)
  • Vulnerable System Impact Availability (VA): Low (L)
  • Subsequent System Impact Confidentiality (SC): None (N)
  • Subsequent System Impact Integrity (SI): None (N)
  • Subsequent System Impact Availability (SA): None (N)
  • Provider Urgency (U): Amber (Amber)
  • Modified Attack Vector (MAV): Network (N)
  • Modified Attack Complexity (MAC): Low (L)
  • Modified Attack Requirement (MAT): None (N)
  • Modified Privileges Required (MPR): None (N)
  • Modified User Interaction (MUI): None (N)
  • Modified Vulnerable System Impact Confidentiality (MVC): None (N)
  • Modified Vulnerable System Impact Integrity (MVI): None (N)
  • Modified Vulnerable System Impact Availability (MVA): Low (L)
  • Modified Subsequent System Impact Confidentiality (MSC): Negligible (N)
  • Modified Subsequent System Impact Integrity (MSI): Negligible (N)
  • Modified Subsequent System Impact Availability (MSA): Negligible (N)
  • Safety (S): Not Defined (X)
  • Automatable (AU): Not Defined (X)
  • Recovery (R): Not Defined (X)
  • Value Density (V): Not Defined (X)
  • Vulnerability Response Effort (RE): Not Defined (X)
  • Confidentiality Req. (CR): Not Defined (X)
  • Integrity Req. (IR): Not Defined (X)
  • Availability Req. (AR): Not Defined (X)
  • Exploit Maturity (E): Not Defined (X)
updated 2 days, 12 hours ago by @LeSuisse Activity log
  • Created suggestion 2 days, 17 hours ago
  • @LeSuisse ignored
    15 packages
    • luaPackages.luaunbound
    • lua51Packages.luaunbound
    • lua52Packages.luaunbound
    • lua53Packages.luaunbound
    • lua54Packages.luaunbound
    • lua55Packages.luaunbound
    • luajitPackages.luaunbound
    • prometheus-unbound-exporter
    • python312Packages.pyunbound
    • python313Packages.pyunbound
    • python314Packages.pyunbound
    • haskellPackages.unbound-generics
    • haskellPackages.unbounded-delays
    • haskellPackages.unbound-kind-generics
    • haskellPackages.unbound-generics-unify
    2 days, 13 hours ago
  • @LeSuisse ignored maintainer @Scrumplex 2 days, 12 hours ago maintainer.ignore
  • @LeSuisse accepted 2 days, 12 hours ago
  • @LeSuisse published on GitHub 2 days, 12 hours ago
Degradation of service with unbounded NSEC3 hash calculations

NLnet Labs Unbound up to and including version 1.25.0 has a vulnerability in the DNSSEC validator where the code path to consult the negative cache for DS records does not take into account the limit on NSEC3 hash calculations introduced in 1.19.1. This leads to degradation of service during the attack. An adversary that controls a DNSSEC signed zone can exploit this by signing NSEC3 records with acceptably high iterations for child delegations and querying a vulnerable Unbound. Unbound will keep performing the allowed hash calculations on the NSEC3 records and will not limit the work by the mitigation introduced in 1.19.1. As a side effect, a global lock for the negative cache will be held for the duration of the hashing, blocking other threads that need to consult the negative cache. Coordinated attacks could raise the vulnerability to denial of service. Unbound 1.25.1 contains a patch with a fix to bound the vulnerable code path with the existing limit for NSEC3 hash calculations.

Affected products

Unbound
  • <1.25.1

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Ignored maintainers (1)