Memory Corruption Vulnerability in BIND 9 by ISC
CVE-2026-94300

8.1HIGH

Key Information:

Vendor

Isc
Status
Bind 9
Vendor
CVE Published:
21 October 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-94300?

A vulnerability in BIND 9 allows attackers to capture and replay GSS-TSIG signed UDP messages, leading to potential memory corruption. By exploiting this flaw, an attacker can craft malicious queries to a zone under their control, risking unauthorized remote code execution while the negotiated TSIG key remains valid. This issue affects multiple versions of BIND 9, making it critical for users to review and apply security patches promptly.

Affected Version(s)

BIND 9 9.11.0 <= 9.18.50

BIND 9 9.20.0 <= 9.20.29

BIND 9 9.21.0 <= 9.21.26

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-94300
Created by Ibonok

References

https://kb.isc.org/docs/cve-2026-94300
vendor-advisory
https://downloads.isc.org/isc/bind9/9.20.30
patch
https://downloads.isc.org/isc/bind9/9.21.27
patch

CVSS V3.1

Score:
8.1
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
High
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

While this flaw was discovered in internal testing, ISC would like to thank Dave Aitel from OpenAI who independently discovered and responsibly reported the issue to ISC.
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