High severity · published May 21, 2025
CVE-2025-40775
DNS message with invalid TSIG causes an assertion failure
7.5
CVSS
15.3%
EPSS
No
On KEV
Description
When an incoming DNS protocol message includes a Transaction Signature (TSIG), BIND always checks it. If the TSIG contains an invalid value in the algorithm field, BIND immediately aborts with an assertion failure.
This issue affects BIND 9 versions 9.20.0 through 9.20.8 and 9.21.0 through 9.21.7.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)15.3% · higher than 97% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
B9
BIND 9 · ISC
9.20.0 through 9.20.8; 9.21.0 through 9.21.7 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-40775
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-40775
kb.isc.org
https://kb.isc.org/docs/cve-2025-40775
www.openwall.com
http://www.openwall.com/lists/oss-security/2025/05/21/1
security.netapp.com
https://security.netapp.com/advisory/ntap-20250523-0001/
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