CVE-2023-25403
Access Control in Yf-Exam Project Yf-Exam 1.8.0
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:NCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2023-25403 is a high-severity Authorization Bypass Through User-Controlled Key (CWE-639) vulnerability in Yf-Exam Project Yf-Exam. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Junk Data (T1001.001); ranked in the top 50% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-29358
Vulnerability Data
CleverStupidDog yf-exam v 1.8.0 is vulnerable to Authentication Bypass. The program uses a fixed JWT key, and the stored key uses username format characters. Any user who logged in within 24 hours. A token can be forged with his username…
more
to bypass authentication.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
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.
Enforcing authorization policy and least privilege directly blocks user-controlled key tampering that bypasses access checks.
Logical access controls prevent unauthorized data access that results from missing authorization checks on object references.
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.5.15 directly requires defining and implementing access control rules (including authorization, need-to-know, role-based restrictions, formal requests, and consistency with classification) that stop one user from reaching another's data via a tampered key; the bounded remainder is dynamic or application-specific authorization logic (cross-referenced to 8.26) that may still allow bypass if those downstream rules are flawed.
Managing access rights includes ensuring users can only access their own records and not bypass authorization by altering identifiers.