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    CVE-2026-5950

    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.

    Published:May 20, 2026
    Last Modified:May 26, 2026
    EPS:May 20, 2026
    EPSS Score:0.00091
    CVSS Score:5.3

    Affected Products

    Vendor
    Isc
    Product
    Bind

    Exploits

    https://github.com/billybaraja/cve-2026-5950-bind9-resolver-dos

    Common Attack Pattern Enumeration and Classification (CAPEC)

    No CAPEC recorded yet

    Related CVEs

    CVE-2026-12617 (CVSS 7.5) — The issue is unexpected program termination based on ordering and/or specific content in responses to queries …
    CVE-2026-11605 (CVSS 7.5) — The issue is a resource exhaustion vulnerability associated with DNSSEC validation. BIND always validates all …
    CVE-2026-10723 (CVSS 6.8) — BIND may accept incorrect child-zone NSEC3 records as valid, which could allow an attacker to forge authentica…
    CVE-2026-10822 (CVSS 6.5) — If BIND encounters a particular invalid data structure in a DNS record, it will accept the invalid data, and m…
    CVE-2026-13204 (CVSS 7.5) — If a provably insecure domain is covered by both an NSEC and NSEC3 record at the parent, and there exist an RR…
    CVE-2026-11331 (CVSS 7.5) — An attacker who knows (or guesses) that a resolver uses RPZ with wildcard CNAME policies can craft query names…
    CVE-2026-11622 (CVSS 7.5) — A DNSSEC validating resolver that is under a random subdomain attack against a DNSSEC-signed zone can suffer f…
    CVE-2026-11721 (CVSS 7.5) — It is possible for an attacker's zone to respond to a query with an RRSIG that has a smaller number of labels …
    CVE-2026-13321 (CVSS 8.6) — The BIND resolver accepts validly-signed NSEC records where the "Next Domain Name" field points outside the si…
    CVE-2026-5947 (CVSS 7.5) — Undefined behavior may result due to a race condition leading to a use-after-free violation. If BIND receives…

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High