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Medium 5.3Published Jun 23, 2026

CVE-2026-56762Hono - Missing Cookie Name Validation in setCookie()

Updated under an hour ago ()

Does this affect you?

It affects Hono. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

Hono before 4.12.12 does not validate cookie names on the write path in the setCookie(), serialize(), and serializeSigned() functions, allowing invalid characters such as control characters (e.g. \r or \n) when an application passes a user-controlled cookie name. This can produce malformed Set-Cookie header values. In modern runtimes such as Node.js and Cloudflare Workers, such invalid header values are rejected and cause a runtime error before the response is sent, so header injection or response splitting could not be reproduced; the issue primarily affects correctness and robustness, resulting in runtime errors (availability) rather than confirmed header injection.

CVSS
5.3 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness (CWE)
CWE-20
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
VulnCheck
NVD analysis
Deferred
Record last updated
Jun 24, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
Hono Hono
hono:hono (from the name)
before 4.12.12; 4.12.12 not affected
CNA record

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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