Executive brief
Hono, a popular web framework, contained a flaw in how it verified user credentials. Because the system stopped checking a password as soon as it found a wrong character, an attacker could theoretically measure these tiny differences in response time to guess valid login information. While difficult to execute in practice, this could lead to unauthorized access to protected parts of an application.
Technical details
A timing discrepancy vulnerability (CWE-208) exists in Hono's basicAuth and bearerAuth middlewares prior to version 4.11.10. The root cause is the use of standard JavaScript strict equality (===) within the timingSafeEqual function when comparing hash values. Because JavaScript string comparisons terminate early upon encountering a mismatched character, an attacker can perform high-precision timing analysis over a network to bit-flip or character-guess valid credentials. This is a high-complexity attack requiring a stable network environment to measure micro-fluctuations in response times. The issue was mitigated in version 4.11.10 by implementing a constant-time comparison method that avoids early termination.
Affected products
- Hono Hono < 4.11.10
Timeline
- 2026-02-18: advisory: GitHub Security Advisory published
- 2026-07-15: disclosed: NVD publication date
- 2026-07-15: patched: Fix confirmed in version 4.11.10