VDB-316705 · CVE-2025-40777 · EUVD-2025-21736

ISC BIND up to 9.20.10/9.20.10-S1/9.21.9 named assertion

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.3	$0-$5k	0.00

Summaryinfo

A vulnerability marked as critical has been reported in ISC BIND up to 9.20.10/9.20.10-S1/9.21.9. This issue affects some unknown processing of the component named. This manipulation causes assertion. This vulnerability is registered as CVE-2025-40777. Remote exploitation of the attack is possible. No exploit is available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability has been found in ISC BIND up to 9.20.10/9.20.10-S1/9.21.9 and classified as critical. Affected by this vulnerability is an unknown code of the component named. The manipulation with an unknown input leads to a assertion vulnerability. The CWE definition for the vulnerability is CWE-617. The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary. As an impact it is known to affect availability. The summary by CVE is:

If a `named` caching resolver is configured with `serve-stale-enable` `yes`, and with `stale-answer-client-timeout` set to `0` (the only allowable value other than `disabled`), and if the resolver, in the process of resolving a query, encounters a CNAME chain involving a specific combination of cached or authoritative records, the daemon will abort with an assertion failure. This issue affects BIND 9 versions 9.20.0 through 9.20.10, 9.21.0 through 9.21.9, and 9.20.9-S1 through 9.20.10-S1.

The advisory is shared at kb.isc.org. This vulnerability is known as CVE-2025-40777 since 04/16/2025. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Neither technical details nor an exploit are publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 242301 (SUSE SLED15 / SLES15 Security Update : bind (SUSE-SU-2025:02349-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 9.18.37 or 9.18.37-S1 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (242301), EUVD (EUVD-2025-21736) and CERT Bund (WID-SEC-2025-1585). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

Internet Systems Consortium BIND

Productinfo

Type

Domain Name Software

Vendor

Name

BIND

Version

License

open-source

Website

Vendor: https://www.isc.org/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.5
VulDB Meta Temp Score: 7.3

VulDB Base Score: 7.5
VulDB Temp Score: 7.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.5
CNA Vector (isc): 🔒

CVSSv2info

AV	AC	Au	C	I	A
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Assertion
CWE: CWE-617
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 242301
Nessus Name: SUSE SLED15 / SLES15 Security Update : bind (SUSE-SU-2025:02349-1)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: BIND 9.18.37/9.18.37-S1

Timelineinfo

04/16/2025 CVE reserved
07/16/2025 +91 days Advisory disclosed
07/16/2025 +0 days VulDB entry created
07/18/2025 +2 days VulDB entry last update

Sourcesinfo

Vendor: isc.org

Advisory: kb.isc.org
Status: Confirmed

CVE: CVE-2025-40777 (🔒)
GCVE (CVE): GCVE-0-2025-40777
GCVE (VulDB): GCVE-100-316705
EUVD: 🔒
CERT Bund: WID-SEC-2025-1585 - Internet Systems Consortium BIND: Mehrere Schwachstellen

Entryinfo

Created: 07/16/2025 20:05
Updated: 07/18/2025 22:11
Changes: 07/16/2025 20:05 (64), 07/16/2025 21:19 (1), 07/17/2025 11:23 (7), 07/18/2025 22:11 (2)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.