5.9Medium
CVE-2026-93750
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.
What this means for your business
- An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.
- FIRST's prediction model gives it a 0.4% chance of attack attempts being seen in the next 30 days, ranking above 28% of all known flaws.
What to do
- 1Ask your IT team or provider whether any of your systems use the affected product.
- 2If you do, follow the vendor's guidance. No patch reference has been published yet.
Not sure if your company is exposed?
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Scoring
- CVSS
- 5.9 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N- CVSS v4
- 8.2
- Weakness
- CWE-436
- Assigned by
- disclosure@vulncheck.com
Dates
- Published
- 2026-09-18
- Last modified
- 2026-09-18
- Sources
- NVD
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