SB2026091658 - Multiple vulnerabilities in ISC BIND

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Main Vulnerability Database SB2026091658

SB2026091658 - Multiple vulnerabilities in ISC BIND

Published: September 16, 2026

Security Bulletin ID SB2026091658
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 14
Exploitation vector Remote access
Highest impact Denial of service

Breakdown by Severity

Medium 93% Low 7%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 14 vulnerabilities.


1) Resource exhaustion (CVE-ID: CVE-2026-81736)

CWE-ID: CWE-400 - Resource exhaustion

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to inefficient resource consumption in the BIND resolver when querying the root of a cached tree of SVCB/HTTPS AliasMode records. A remote attacker can send a query for the root of the cached record tree to cause a denial of service.


2) Input validation error (CVE-ID: CVE-2026-78301)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: 5.9 [CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote user to cause BIND to return attacker-supplied DNS data.

The vulnerability exists due to improper input validation in the named zone database when loading a malformed zone containing an NS or DNAME node above its origin. A remote privileged user can insert a malformed zone to cause BIND to return attacker-supplied DNS data.

On servers that also provide recursion, BIND can follow the locally sourced zone cut and cache attacker-supplied records for names outside the configured zone. On purely authoritative servers, queries may return out-of-zone referrals without the AA flag.


3) Input validation error (CVE-ID: CVE-2026-77692)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to improper handling of cryptographically invalid SIG(0) records in named when processing crafted DNS-over-HTTPS requests. A remote attacker can send a crafted DNS-over-HTTPS request containing a cryptographically invalid SIG(0) record and prematurely close the transport connection to cause a denial of service.


4) Reachable assertion (CVE-ID: CVE-2026-76163)

CWE-ID: CWE-617 - Reachable Assertion

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to a reachable assertion in BIND named TKEY query handling when processing a TKEY query. A remote attacker can send a TKEY query to cause a denial of service.

The issue occurs when the named.conf configuration file contains no global options block.


5) Insufficient verification of data authenticity (CVE-ID: CVE-2026-19941)

CWE-ID: CWE-345 - Insufficient Verification of Data Authenticity

CVSSv4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to poison the DNS cache.

The vulnerability exists due to insufficient verification of data authenticity in the checkwildcard() function of the named resolver when validating wildcard-nonexistence proofs. A remote attacker can provide an out-of-zone NSEC record as proof that a wildcard does not exist to poison the DNS cache.

Exploitation requires control at the same or an upstream level of the zone name.


6) Numeric Truncation Error (CVE-ID: CVE-2026-19667)

CWE-ID: CWE-197 - Numeric Truncation Error

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to numeric truncation in dns_ncache_add() when processing a negative answer exactly 65536 bytes long from an attacker-controlled authoritative server. A remote attacker can return such a negative answer to cause a denial of service.


7) Use-after-free (CVE-ID: CVE-2026-19666)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to use-after-free in query_addnoqnameproof() via the DNS64 filter64 path when processing a malformed applicable answer from an authoritative server. A remote attacker can send a malformed applicable DNS answer to cause a denial of service.

Only resolvers configured to use dns64 are affected.


8) Use-after-free (CVE-ID: CVE-2026-19662)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to a use-after-free in qpcache NOQNAME proof handling when processing crafted DNSSEC responses from an attacker-controlled authoritative server. A remote attacker can send a particular sequence of crafted DNS answers to cause a denial of service.

Exploitation requires inducing the resolver to issue multiple queries for a DNSSEC-signed zone and relies on the responses arriving in a particular order and with particular timing.


9) Memory leak (CVE-ID: CVE-2026-81563)

CWE-ID: CWE-401 - Missing release of memory after effective lifetime

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to a failure to properly deallocate internal resources in SVCB/HTTPS AliasMode additional-data processing when processing an SVCB/HTTPS AliasMode record that references 14 or more SVCB/HTTPS ServiceMode records. A remote attacker can cause the resolver to process such records to cause a denial of service.

Repeated exploitation is required to exhaust resources.


10) Input validation error (CVE-ID: CVE-2026-80274)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to improper validation of a NOQNAME proof in the BIND validating resolver when processing DNSSEC responses. A remote attacker can send a DNS response containing a valid wildcard answer and signed NSEC3 proof followed by an unsigned NSEC record at the same owner name to cause a denial of service.

The resolver must query a DNSSEC-signed authoritative zone.


11) Insufficient verification of data authenticity (CVE-ID: CVE-2026-77119)

CWE-ID: CWE-345 - Insufficient Verification of Data Authenticity

CVSSv4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to cause DNS cache poisoning.

The vulnerability exists due to insufficient verification of data authenticity in BIND 9 NSEC3 insecure-referral proof validation when processing insecure-referral proofs. A remote attacker can provide a validly signed NSEC3 record from an unrelated sibling zone to cause DNS cache poisoning.


12) Resource exhaustion (CVE-ID: CVE-2026-75029)

CWE-ID: CWE-400 - Resource exhaustion

CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to improper handling of duplicate singleton RDATA records in the named message parser when processing query responses. A remote attacker can send a query response containing multiple identical copies of a record that should exist only once to cause a denial of service.


13) Resource exhaustion (CVE-ID: CVE-2026-19668)

CWE-ID: CWE-400 - Resource exhaustion

CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to uncontrolled resource consumption in the BIND recursive resolver when processing large numbers of invalid DNSSEC records. A remote attacker can cause the resolver to process excessive invalid DNSSEC cryptographic material to cause a denial of service.


14) Insufficient verification of data authenticity (CVE-ID: CVE-2026-19033)

CWE-ID: CWE-345 - Insufficient Verification of Data Authenticity

CVSSv4: 8.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to add arbitrary data to a zone.

The vulnerability exists due to improper verification of TSIG signatures in named IXFR processing when processing a multi-message TCP IXFR for a TSIG-restricted secondary zone. A remote attacker can send an IXFR transfer without a valid TSIG signature to add arbitrary data to a zone.


Remediation

Install update from vendor's website.

References