GHSA-q7jf-gf43-6x6p: hono (CVE-2025-71381)

Package	Ecosystem	Affected	Fixed in
hono	npm	<4.10.3	4.10.3

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

The npm package hono, versions before 4.10.3, has a flaw in its CORS middleware that copied the request's Vary header into the response when origin was not set to "*". An attacker who can send requests to an affected application could influence the Vary value, which may cause cache key pollution or inconsistent CORS handling, mainly where shared caches or proxies rely on Vary. The source says there is no direct confidentiality, integrity, or availability impact in default configurations. Upgrade to hono 4.10.3 or later.

Written 31 Oct 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
6.9	Medium	4.0	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N	CNA (VulnCheck)

CISA KEV Not listed.
EPSS 0.0029, the 21st percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 13:34 UTC First seen by agentprime
31 Oct 2026, 13:34 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.