Cyber Resilience

CVE-2025-5994

Published
16 July 2025
Modified
17 June 2026
CVSS Score v4 8.7
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:U/V:C/RE:X/U:X
EPSS Score 0.0019 9th percentile
Risk Priority 43 floored blend · peak EPSS

Summary

CVE-2025-5994 is a high-severity Acceptance of Extraneous Untrusted Data With Trusted Data (CWE-349) vulnerability in Nlnetlabs (inferred from references). Its CVSS base score is 8.7 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Subvert Trust Controls (T1553); ranked at the 9th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to AC-4 (Information Flow Enforcement) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

A multi-vendor cache poisoning vulnerability named 'Rebirthday Attack' has been discovered in caching resolvers that support EDNS Client Subnet (ECS). Unbound is also vulnerable when compiled with ECS support, i.e., '--enable-subnet', AND configured to send ECS information along with queries…

more

to upstream name servers, i.e., at least one of the 'send-client-subnet', 'client-subnet-zone' or 'client-subnet-always-forward' options is used. Resolvers supporting ECS need to segregate outgoing queries to accommodate for different outgoing ECS information. This re-opens up resolvers to a birthday paradox attack (Rebirthday Attack) that tries to match the DNS transaction ID in order to cache non-ECS poisonous replies.

CWE(s)
CWE-349

Related Threats

MITRE ATT&CK Enterprise Techniques

T1553 Subvert Trust Controls Defense Impairment
Adversaries may undermine security controls that will either warn users of untrusted activity or prevent execution of untrusted programs.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-21094Shared CWE-349
CVE-2026-42960Shared CWE-349
CVE-2026-50252Shared CWE-349
CVE-2025-11703Shared CWE-349
CVE-2025-1680Shared CWE-349
CVE-2025-48804Shared CWE-349
CVE-2025-40776Shared CWE-349
CVE-2026-35641Shared CWE-349
CVE-2026-41120Shared CWE-349
CVE-2024-52555Shared CWE-349

Affected Assets

Nlnetlabs
—
inferred from references and description; NVD did not file a CPE for this CVE

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 5 hardening rules · 2 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V1.2.2
  • V10.4.7
  • V3.7.3
  • V5.3.1

Mitigating Controls (NIST 800-53 r5) AI

AC-4 Information Flow Enforcement good match

Information flow enforcement can block untrusted data from being accepted or processed as if it were trusted.

SI-10 Information Input Validation good match

Input validation directly stops acceptance of untrusted data mixed into trusted inputs.

SC-16 Transmission of Security and Privacy Attributes partial match

Associating security attributes with data allows the system to distinguish and reject extraneous untrusted portions.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly address proper trust-boundary enforcement and input validation, preventing this class of weakness during development.

PR.DS-01 partial match
prevents

Cryptographic integrity checks on data-at-rest can detect tampering or substitution of untrusted content mixed with trusted data.

PR.DS-02 partial match
prevents

Cryptographic integrity mechanisms on data-in-transit can prevent acceptance of extraneous untrusted data by validating origin and detecting modification.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing can detect the weakness but does not itself implement preventive controls.

A.8.25 Secure development life cycle partial match
prevents

Secure development lifecycle mandates input validation and trust-boundary enforcement that directly prevents acceptance of untrusted data alongside trusted data.

A.8.26 Application security requirements partial match
prevents

Application security requirements explicitly call for strict separation and validation of trusted versus untrusted data sources.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles require explicit trust boundaries and data-origin checks that mitigate mixing of trusted and untrusted inputs.

A.8.28 Secure coding partial match
prevents

Secure coding standards mandate input sanitization and provenance checks that prevent acceptance of extraneous untrusted data.

A.8.3 Information access restriction none match
none

Information access restriction limits who can supply data but does not address validation of data origin or trust level.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (1 rule)
  • V-248574 YUM must be configured to prevent the installation of patches, service packs, device drivers, or OL 8 system components that have not been digitally signed using a certificate that is recognized and approved by the organization. prevents CWE-349

References