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.

Attack Vector Network

Attack Complexity High

Privileges Required None

Attack Requirements Present

User Interaction None

Vulnerable System Confidentiality Impact High

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity High

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact None

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.0035.

Exploitation poc

Automatable no

Technical Impact partial

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
kornelski http-cache-semantics unaffected
Version Status Constraints
0 affected ≤ 4.2.0

No data.

No data.

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Project Subscriptions

Vendors Products
Http-cache-semantics Project Subscribe
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Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

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

Fri, 18 Sep 2026 21:30:00 +0000

Type Values Removed Values Added
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.
Title http-cache-semantics through 4.2.0 Cross-Client Cache Disclosure via Vary Wildcard
First Time appeared Http-cache-semantics Project
Http-cache-semantics Project http-cache-semantics
Weaknesses CWE-436
CPEs cpe:2.3:a:http-cache-semantics_project:http-cache-semantics:*:*:*:*:*:*:*:*
Vendors & Products Http-cache-semantics Project
Http-cache-semantics Project http-cache-semantics
References
Metrics cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N'}

cvssV4_0

{'score': 8.2, 'vector': 'CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-09-18T18:03:20.270Z

Reserved: 2026-09-18T16:30:17.776Z

Link: CVE-2026-93750

cve-icon Vulnrichment

Updated: 2026-09-18T18:03:16.325Z

cve-icon NVD

Status : Received

Published: 2026-09-18T18:18:33.633

Modified: 2026-09-18T18:18:33.633

Link: CVE-2026-93750

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-19T16:45:16Z

Weaknesses