CVE-2026-94300: CWE-415 Double Free in ISC BIND 9
Description
CVE-2026-94300 is a high-severity vulnerability in ISC BIND 9 involving a double free condition triggered by replaying GSS-TSIG signed UDP messages. An attacker who captures a previously signed UDP message can replay it while the TSIG key is still valid, potentially causing memory corruption in the named daemon. By sending crafted queries to a zone controlled by the attacker, remote code execution may be achievable. This affects multiple BIND 9 version ranges including 9.11.0 through 9.18.50 and others as specified.
CVSS v3.1
Score 8.1high
Affected software
ISC
BIND 9
pkg:github/isc/bind9Run on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability (CVE-2026-94300) in ISC BIND 9 arises from a double free (CWE-415) triggered by replaying GSS-TSIG signed UDP messages. The flaw allows an attacker who can capture a valid signed UDP message to replay it during the validity of the negotiated TSIG key, causing memory corruption in the named DNS server process. Coupled with crafted DNS queries to an attacker-controlled zone, this may lead to remote code execution. The affected versions include 9.11.0 through 9.18.50, 9.20.0 through 9.20.29, 9.21.0 through 9.21.26, and their respective S1 variants.
Potential Impact
Successful exploitation can lead to remote code execution with high confidentiality, integrity, and availability impact. The vulnerability allows an unauthenticated attacker to cause memory corruption and potentially execute arbitrary code remotely on the DNS server running vulnerable BIND 9 versions.
Mitigation Recommendations
No explicit patch or remediation details are provided in the input data. Patch status is not yet confirmed — check the ISC vendor advisory for current remediation guidance. Until a fix is confirmed, restrict network access to the named service and monitor for suspicious replayed GSS-TSIG UDP messages if possible.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- isc
- Date Reserved
- 2026-09-21T09:46:27.369Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6ad8b86f2cdf04f656f0cad3
Added to database: 10/21/2026, 13:04:47 UTC
Last enriched: 10/21/2026, 13:15:52 UTC
Last updated: 10/21/2026, 13:40:20 UTC
Views: 5
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