Cyber Resilience

CVE-2025-40918

Published
16 July 2025
Modified
17 June 2026
CVSS Score v3.1 6.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
EPSS Score 0.0039 32th percentile
Risk Priority 51 floored blend · peak EPSS

Summary

CVE-2025-40918 is a medium-severity PRNG (CWE-338) vulnerability. Its CVSS base score is 6.5 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Forge Web Credentials (T1606); ranked at the 32th 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 SA-11 (Developer Testing and Evaluation) and SC-12 (Cryptographic Key Establishment and Management) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A04:2025 Cryptographic Failures

EU & UK References

Vulnerability Data

Authen::SASL::Perl::DIGEST_MD5 versions 2.04 through 2.1800 for Perl generates the cnonce insecurely. The cnonce (client nonce) is generated from an MD5 hash of the PID, the epoch time and the built-in rand function. The PID will come from a small set…

more

of numbers, and the epoch time may be guessed, if it is not leaked from the HTTP Date header. The built-in rand function is unsuitable for cryptographic usage. According to RFC 2831, The cnonce-value is an opaque quoted string value provided by the client and used by both client and server to avoid chosen plaintext attacks, and to provide mutual authentication. The security of the implementation depends on a good choice. It is RECOMMENDED that it contain at least 64 bits of entropy.

CWE(s)
CWE-338CWE-340

Related Threats

MITRE ATT&CK Enterprise Techniques

T1606 Forge Web Credentials Credential Access
Adversaries may forge credential materials that can be used to gain access to web applications or Internet services.
attack.mitre.org →
T1606.001 Web Cookies Credential Access
Adversaries may forge web cookies that can be used to gain access to web applications or Internet services.
attack.mitre.org →
T1110 Brute Force Credential Access
Adversaries may use brute force techniques to gain access to accounts when passwords are unknown or when password hashes are obtained.
attack.mitre.org →
T1185 Browser Session Hijacking Collection
Adversaries may take advantage of security vulnerabilities and inherent functionality in browser software to change content, modify user-behaviors, and intercept information as part of various browser session hijacking techniques.
attack.mitre.org →
T1558 Steal or Forge Kerberos Tickets Credential Access
Adversaries may attempt to subvert Kerberos authentication by stealing or forging Kerberos tickets to enable [Pass the Ticket](https://attack.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-5083Shared CWE-338, CWE-340
CVE-2025-40920Shared CWE-338, CWE-340
CVE-2025-40932Shared CWE-338, CWE-340
CVE-2025-40931Shared CWE-338, CWE-340
CVE-2026-9692Shared CWE-338, CWE-340
CVE-2026-3256Shared CWE-338, CWE-340
CVE-2025-40924Shared CWE-338, CWE-340
CVE-2025-40919Shared CWE-338, CWE-340
CVE-2026-9733Shared CWE-338, CWE-340
CVE-2025-40923Shared CWE-338, CWE-340

Affected Assets

—
DIGEST_MD5
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)
  • 9 hardening rules · 4 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V7.2.3
  • V11.5.1
  • V11.3.4

Mitigating Controls (NIST 800-53 r5) AI

SC-13 Cryptographic Protection good match

Requiring specific approved cryptography for protection directly mandates use of strong PRNGs instead of weak ones.

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation can discover predictable number generation through targeted analysis or fuzzing of identifier creation routines.

SC-12 Cryptographic Key Establishment and Management good match

Cryptographic key establishment and management mandates proper entropy and randomness during generation, directly stopping predictable identifiers at the source.

IA-5 Authenticator Management partial match

Authenticator management requires secure initial distribution and handling of authenticators, structurally preventing predictable values from being usable.

SA-8 Security and Privacy Engineering Principles partial match

Engineering principles applied during design and development include selection of cryptographically strong random number generation.

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 explicitly require cryptographically strong RNG selection and usage in security contexts.

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.8.24 Use of cryptography mostly match
prevents

Mandates use of approved cryptographic controls, directly requiring cryptographically strong RNGs.

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

Security testing can detect use of weak random number generators.

A.8.25 Secure development life cycle partial match
prevents

Secure SDLC processes should catch weak PRNG usage during design and code review.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify cryptographically strong random number generation.

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

Secure engineering principles include selection of appropriate cryptographic primitives.

A.8.28 Secure coding partial match
prevents

Secure coding standards prohibit use of weak PRNGs in security contexts.

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 (3 rules)
  • V-248524 OL 8 must implement NIST FIPS-validated cryptography for the following: To provision digital signatures, to generate cryptographic hashes, and to protect data requiring data-at-rest protections in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. prevents CWE-340
  • V-248563 The OL 8 SSH server must be configured to use strong entropy. prevents CWE-338
  • V-248600 OL 8 must have the packages required to use the hardware random number generator entropy gatherer service. prevents CWE-340
RHEL 7 (1 rule)
  • V-204497 The Red Hat Enterprise Linux operating system must implement NIST FIPS-validated cryptography for the following: to provision digital signatures, to generate cryptographic hashes, and to protect data requiring data-at-rest protections in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. prevents CWE-340
RHEL 8 (2 rules)
  • V-230253 RHEL 8 must ensure the SSH server uses strong entropy. prevents CWE-338
  • V-244527 RHEL 8 must have the packages required to use the hardware random number generator entropy gatherer service. prevents CWE-340
Ubuntu 22.04 (1 rule)
  • V-260650 Ubuntu 22.04 LTS must implement NIST FIPS-validated cryptography to protect classified information and for the following: To provision digital signatures, to generate cryptographic hashes, and to protect unclassified information requiring confidentiality and cryptographic protection in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. prevents CWE-338

References