WWW::OAuth: Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
CVE-2025-40905 is a high-severity use of cryptographically weak pseudo-random number generator (PRNG) vulnerability in WWW::OAuth from DBOOK, with a CVSS 3.1 base score of 7.3 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected WWW::OAuth versions: 1.000 and earlier. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.3% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of WWW::OAuth you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| DBOOK | WWW::OAuth | 1.000 and earlier | Not stated |
| Dbook | Www | 1.000 and earlier | Not 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
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- LowSome restricted data can be read.
- Integrity
- LowLimited modification of data is possible.
- Availability
- LowPerformance or availability is reduced.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L. Scored by CISA (ADP).
Official description
WWW::OAuth 1.000 and earlier for Perl uses the rand() function as the default source of entropy, which is not cryptographically secure, for cryptographic functions.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
The product uses a Pseudo-Random Number Generator (PRNG) in a security context, but the PRNG's algorithm is not cryptographically strong.
How developers prevent this class of flaw
- Use functions or hardware which use a hardware-based random number generation for all crypto. This is the recommended solution. Use CyptGenRandom on Windows, or hw_rand() on Linux.
More Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) vulnerabilities (CWE-338)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- perldoc.perl.org/functions/randThird Party Advisory
- security.metacpan.org/docs/guides/random-data-for-security.htmlThird Party Advisory
- openwall.com/lists/oss-security/2026/02/13/1Mailing List, Third Party Advisory
Other references
- metacpan.org/release/DBOOK/WWW-OAuth-1.000/source/lib/WWW/OAuth.pm#L86Issue Tracking, Product
Recent Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) vulnerabilities
- 9.4 Critical severity
- 7.7 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 7.4 High severity
- 9.1 Critical severity
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