CyberSecBulletin
CVE-2025-40778NVD status: Deferred

BIND 9: Acceptance of Extraneous Untrusted Data With Trusted Data

CVE-2025-40778 is a high-severity acceptance of extraneous untrusted data with trusted data vulnerability in BIND 9 from ISC, with a CVSS 3.1 base score of 8.6 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected BIND 9 versions: 9.11.0 through 9.16.50; 9.18.0 through 9.18.39; 9.20.0 through 9.20.13, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.77% chance of exploitation within 30 days, higher than 56% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of BIND 9 you run against the affected versions below, and install the vendor's latest release.
  2. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
ISCBIND 99.11.0 through 9.16.50; 9.18.0 through 9.18.39; 9.20.0 through 9.20.13; 9.21.0 through 9.21.12; 9.11.3-S1 through 9.16.50-S1; 9.18.11-S1 through 9.18.39-S1; 9.20.9-S1 through 9.20.13-S1Not stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
ChangedThe attack can reach beyond the vulnerable component into other systems.
Confidentiality
NoneNo data is disclosed.
Integrity
HighData or code can be modified at will.
Availability
NoneAvailability is not affected.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N. Scored by CNA (isc.org).

Official description

Under certain circumstances, BIND is too lenient when accepting records from answers, allowing an attacker to inject forged data into the cache. This issue affects BIND 9 versions 9.11.0 through 9.16.50, 9.18.0 through 9.18.39, 9.20.0 through 9.20.13, 9.21.0 through 9.21.12, 9.11.3-S1 through 9.16.50-S1, 9.18.11-S1 through 9.18.39-S1, and 9.20.9-S1 through 9.20.13-S1.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Acceptance of Extraneous Untrusted Data With Trusted Data

The product, when processing trusted data, accepts any untrusted data that is also included with the trusted data, treating the untrusted data as if it were trusted.

More Acceptance of Extraneous Untrusted Data With Trusted Data vulnerabilities (CWE-349)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in BIND 9

All BIND 9 vulnerabilities

Recent Acceptance of Extraneous Untrusted Data With Trusted Data vulnerabilities

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