CVE-2025-71381

mediumpriority · track · 0EPSS 0.003 · 22 %ileEUUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
0.29% (22nd) EPSS
CVSS 6.5 · medium
Is it mine?
2 products
Check your exposure
Who says so?
3 sources
cnnvd · enisa_euvd · osv

EPSS · scored 2026-10-27

Hono before 4.10.2 (fixed in 4.10.3) contains a flaw in its CORS middleware: when the origin is not set to "*", the middleware copies the Vary header from the incoming request into the response. Because Vary is a response header that should be managed by the server, an attacker can supply arbitrary Vary values that are reflected into the response, potentially causing cache key pollution and inconsistent CORS enforcement in environments that rely on shared caches or proxies.

01

cvss

Technical severity, 0–10. One row per scoring source.

6.9
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–medium · 2.7–6.9

v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:Nsecondary · disclosure@vulncheck.comexploitability 3.9 · impact 2.5
v3.14.2mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:Nsecondary · OSV
v4.06.9mediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:Nsecondary · ENISA EU
v4.06.9mediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Xsecondary · disclosure@vulncheck.com
v4.02.7lowCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Xsecondary · CVSS-BT (t0sche)
02

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: yes · Technical Impact: partialcoordinatorcisa_ssvcUS
03

weaknesses

The CWE weakness classes this flaw belongs to.

04

affected products (2)

Products and version ranges known to be affected.

05

advisories (1)

Vendor and ecosystem advisories describing this.

  • GHSA-q7jf-gf43-6x6pHono vulnerable to Vary Header Injection leading to potential CORS Bypass2025-10-24ghsa · osvUS

    ### Summary A flaw in the CORS middleware allowed request `Vary` headers to be reflected into the response, enabling attacker-controlled `Vary` values and potentially affecting cache behavior. ### Details The middleware previously copied the `Vary` header from the request when `origin` was not set to `"*"`. Since `Vary` is a response header that should only be managed by the server, this could allow an attacker to influence caching behavior or cause inconsistent CORS handling. Most environments will see impact only when shared caches or proxies rely on the `Vary` header. The practical effect varies by configuration. ### Impact May cause cache key pollution and inconsistent CORS enforcement in certain setups. No direct confidentiality, integrity, or availability impact in default configurations. ### Resolution Update to the latest patched release. The CORS middleware has been corrected to handle `Vary` exclusively as a response header.

06

also known as (3)

Other names and identifiers for this entity.

07

sources

Which sources assert this record, and when.

published 2026-06-30modified 2026-07-02
08

references (6)

External citations — patches, advisories, analysis.

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