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.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

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 Low

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 0.004.

Exploitation poc

Automatable yes

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
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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#L425-L441 cve-icon cve-icon
https://github.com/kornelski/http-cache-semantics/blob/f01112e954b83cfa8765b633ba880e5e980aa54c/index.js#L603-L623 cve-icon cve-icon
https://github.com/kornelski/http-cache-semantics/issues/56 cve-icon cve-icon cve-icon
https://www.vulncheck.com/advisories/http-cache-semantics-through-4.2.0-cross-user-cache-disclosure-via-max-stale 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 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.
Title http-cache-semantics through 4.2.0 Cross-User Cache Disclosure via max-stale
First Time appeared Http-cache-semantics Project
Http-cache-semantics Project http-cache-semantics
Weaknesses CWE-524
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': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'}

cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-09-18T20:05:12.650Z

Reserved: 2026-09-18T16:30:17.085Z

Link: CVE-2026-93748

cve-icon Vulnrichment

Updated: 2026-09-18T20:04:44.166Z

cve-icon NVD

Status : Received

Published: 2026-09-18T18:18:33.330

Modified: 2026-09-18T20:17:33.510

Link: CVE-2026-93748

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-19T16:30:17Z

Weaknesses