---
id: CVE-2026-93750
title: >-
  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
summary: >-
  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
  previous…
severity: medium
cvss: 5.9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N'
cwe:
  - CWE-436
  - CWE-524
vendor: kornelski
product: http-cache-semantics
affected:
  - http-cache-semantics <= 4.2.0
published: '2026-09-18'
updated: '2026-09-23'
sourceUpdated: '2026-09-23T17:17:49.997'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-93750'
references:
  - url: 'https://github.com/kornelski/http-cache-semantics'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/kornelski/http-cache-semantics/blob/f01112e954b83cfa8765b633ba880e5e980aa54c/index.js#L483-L501
    label: disclosure@vulncheck.com
  - url: 'https://github.com/kornelski/http-cache-semantics/issues/57'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/http-cache-semantics-through-4.2.0-cross-client-cache-disclosure-via-vary-wildcard
    label: disclosure@vulncheck.com
  - url: 'https://github.com/kornelski/http-cache-semantics/issues/57'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-93750.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-93750'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2538846'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-93750'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-93750'
tags:
  - nvd
  - cve.org
  - exploit-available
  - csaf
  - vex
  - red-hat
epss: 0.00445
epssPercentile: 0.38809
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-18T18:03:06.336954Z'
ingestedAt: '2026-09-18T18:47:53.269Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Confidential Compute Attestation, Exploit Intelligence, Gatekeeper 3, Migration Toolkit for Applications 8, Migration Toolkit for Containers, Multicluster Engine for Kubernetes, … · no fix planned: Confidential Compute Attestation, Exploit Intelligence, Gatekeeper 3, Migration Toolkit for Applications 8, … · updated 2026-10-02 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-93750.json)