CVE-2026-93748: Kornelski HTTP-Cache-Semantics

High severity, CVSS 7.5. EPSS: 0.5% chance of exploitation in the next 30 days.

http-cache-semantics through 4.2.0 fails to properly validate security-zeroed cache entries when processing client max-stale directives, allowing unauthenticated attackers to retrieve cached responses belonging to other users. Attackers can request the same URL with a large max-stale value to obtain another user's Set-Cookie session credentials from shared-cache entries that were deliberately zeroed for security reasons.

Affected products

• Kornelski HTTP-Cache-Semantics: up to and including 4.2.0

Published 2026-09-18. Last modified 2026-09-23.