Is CVE-2026-29086 in the CISA KEV catalog?

No. CVE-2026-29086 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-29086?

CVE-2026-29086 has a CVSS v3 base score of 5.4 (MEDIUM).

What is the EPSS score for CVE-2026-29086?

CVE-2026-29086 has an EPSS score of 0.22% (12th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-29086?

Upgrade hono to 4.12.4 or later.

CVE & CISA-KEV Catalog

CVE-2026-29086

MEDIUM

5.4

CVSS v3

NVD

Description

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to version 4.12.4, the setCookie() utility did not validate semicolons (;), carriage returns (\r), or newline characters (\n) in the domain and path options when constructing the Set-Cookie header. Because cookie attributes are delimited by semicolons, this could allow injection of additional cookie attributes if untrusted input was passed into these fields. This issue has been patched in version 4.12.4.

CWE-1113

How to fix

Remediation Available

honoNVD

Affected:< 4.12.4Fixed in:4.12.4CVE-2026-29086derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionRequired

ScopeUnchanged

Impact

ConfidentialityLow

IntegrityLow

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

Exploit Intelligence

0.22%probability of exploitation in 30 days

12thpercentile

Low risk: more likely to be exploited than 12% of all known CVEs.

References

Patch1

github.com

Vendor Advisory1

github.com

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-03-06.