Remote denial of service in ISC BIND



| Updated: 2025-05-23
Risk Medium
Patch available YES
Number of vulnerabilities 1
CVE-ID CVE-2025-40775
CWE-ID CWE-617
Exploitation vector Network
Public exploit Public exploit code for vulnerability #1 is available.
Vulnerable software
 ISC BIND
Server applications / DNS servers

Vendor ISC

Security Bulletin

This security bulletin contains one medium risk vulnerability.

1) Reachable assertion

EUVDB-ID: #VU109620

Risk: Medium

CVSSv4.0: 7.7 [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/E:P/U:Green]

CVE-ID: CVE-2025-40775

CWE-ID: CWE-617 - Reachable Assertion

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a reachable assertion when handling transaction signature (TSIG) in incoming DNS messages. A remote attacker can send specially crafted DNS messages to the affected server and perform a denial of service (DoS) attack.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

ISC BIND: 9.20.0 - 9.21.7

CPE2.3 External links

https://kb.isc.org/docs/cve-2025-40775


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.



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