ISC BIND up to 9.21.25 Recursion recursion

Summaryinfo

A vulnerability classified as problematic was found in ISC BIND up to 9.18.50/9.18.50-S1/9.20.27/9.20.27-S1/9.21.25. Affected by this vulnerability is an unknown functionality of the component Recursion. Such manipulation leads to recursion. This vulnerability is traded as CVE-2026-78301. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in ISC BIND up to 9.18.50/9.18.50-S1/9.20.27/9.20.27-S1/9.21.25. It has been rated as problematic. Affected by this issue is an unknown function of the component Recursion. The manipulation with an unknown input leads to a recursion vulnerability. Using CWE to declare the problem leads to CWE-674. The product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack. Impacted is integrity. CVE summarizes:

A malformed zone may contain an NS or DNAME node above its origin, which `named` treats as a zone cut. If an attacker inserts a malformed zone into a BIND authoritative server (e.g., via zone transfer), queries for names inside the configured zone then lose authoritative status and return an out-of-zone delegation. On a server that also provides recursion BIND can follow this locally sourced cut and cache attacker-supplied data, affecting names outside the configured zone. This situation persists as long as the malformed zone remains in the zone database. This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.27-S1.

The advisory is shared for download at kb.isc.org. This vulnerability is handled as CVE-2026-78301 since 08/24/2026. The exploitation is known to be easy. The attack may be launched remotely. Additional levels of successful authentication are needed for exploitation. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 09/16/2026). The MITRE ATT&CK project declares the attack technique as T1499.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Type

• Domain Name Software

Vendor

• ISC

Name

• BIND

Version

• 9.18.0
• 9.18.1
• 9.18.2
• 9.18.3
• 9.18.4
• 9.18.5
• 9.18.6
• 9.18.7
• 9.18.8
• 9.18.9
• 9.18.10
• 9.18.11
• 9.18.12
• 9.18.13
• 9.18.14
• 9.18.15
• 9.18.16
• 9.18.17
• 9.18.18
• 9.18.19
• 9.18.20
• 9.18.21
• 9.18.22
• 9.18.23
• 9.18.24
• 9.18.25
• 9.18.26
• 9.18.27
• 9.18.28
• 9.18.29
• 9.18.30
• 9.18.31
• 9.18.32
• 9.18.33
• 9.18.34
• 9.18.35
• 9.18.36
• 9.18.37
• 9.18.38
• 9.18.39
• 9.18.40
• 9.18.41
• 9.18.42
• 9.18.43
• 9.18.44
• 9.18.45
• 9.18.46
• 9.18.47
• 9.18.48
• 9.18.49
• 9.18.50
• 9.18.50-S1
• 9.20.0
• 9.20.1
• 9.20.2
• 9.20.3
• 9.20.4
• 9.20.5
• 9.20.6
• 9.20.7
• 9.20.8
• 9.20.9
• 9.20.10
• 9.20.11
• 9.20.12
• 9.20.13
• 9.20.14
• 9.20.15
• 9.20.16
• 9.20.17
• 9.20.18
• 9.20.19
• 9.20.20
• 9.20.21
• 9.20.22
• 9.20.23
• 9.20.24
• 9.20.25
• 9.20.26
• 9.20.27
• 9.20.27-S1
• 9.21.0
• 9.21.1
• 9.21.2
• 9.21.3
• 9.21.4
• 9.21.5
• 9.21.6
• 9.21.7
• 9.21.8
• 9.21.9
• 9.21.10
• 9.21.11
• 9.21.12
• 9.21.13
• 9.21.14
• 9.21.15
• 9.21.16
• 9.21.17
• 9.21.18
• 9.21.19
• 9.21.20
• 9.21.21
• 9.21.22
• 9.21.23
• 9.21.24
• 9.21.25

License

• open-source

Website

• Vendor: https://www.isc.org/

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