What’s Vulnerable › Vulnerabilities

CVE-2026-93750: http-cache-semantics through 4.2.0 Cross-Client Cache Disclosure via Vary Wildcard

• Severity: medium (CVSS 5.9 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-18 · updated 2026-09-23
• Weakness: CWE-436

Description

http-cache-semantics through 4.2.0 contains a cache validation vulnerability in the _varyMatches() function that fails to properly validate Vary header wildcards due to byte-for-byte string comparison. Attackers can request URLs previously fetched by other clients to receive cached responses intended for different users, disclosing sensitive information across clients.

Affected products

• kornelski http-cache-semantics: through 4.2.0

References

• https://github.com/kornelski/http-cache-semantics
• https://github.com/kornelski/http-cache-semantics/blob/f01112e954b83cfa8765b633ba880e5e980aa54c/index.js#L483-L501
• https://github.com/kornelski/http-cache-semantics/issues/57
• https://www.vulncheck.com/advisories/http-cache-semantics-through-4.2.0-cross-client-cache-disclosure-via-vary-wildcard
• https://github.com/kornelski/http-cache-semantics/issues/57

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