Cross-User Cache Disclosure in http-cache-semantics by Kornel S.
CVE-2026-93748

8.7HIGH

Key Information:

Vendor

Kornelski

Status
Http-cache-semantics
Vendor
CVE Published:
18 September 2026

What is CVE-2026-93748?

The http-cache-semantics library version 4.2.0 and earlier has a significant flaw in its handling of security-zeroed cache entries. This vulnerability arises when processing client max-stale directives, which can enable unauthenticated attackers to mistakenly retrieve cached responses meant for other users. By manipulating the max-stale value in requests, attackers can exploit this flaw to access sensitive session cookies that have been zeroed out for security. This creates a pathway for unauthorized access and represents a serious breach of user data privacy.

Affected Version(s)

http-cache-semantics 0 <= 4.2.0

References

https://github.com/kornelski/http-cache-semantics/issues/56
issue-tracking
https://github.com/kornelski/http-cache-semantics
product
https://github.com/kornelski/http-cache-semantics/blob/f0...
technical-description

CVSS V4

Score:
8.7
Severity:
HIGH
Confidentiality:
High
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Wayde Shi (PayPal Cyber Security Team)
.