How severe is CVE-2026-47675?

CVE-2026-47675 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2026-47675 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-47675?

CVE-2026-47675 affects Hono. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-47675?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-47675 have an EU (EUVD) identifier?

Yes. CVE-2026-47675 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-32925.

When was CVE-2026-47675 published?

CVE-2026-47675 was published on 2026-05-28 and last updated on 2026-06-17.

CVE-2026-47675

CVE-2026-47675 is a medium-severity vulnerability in Hono with a CVSS 3.x base score of 4.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-113.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
EPSS exploit prediction: 0% (12th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-32925
Weakness: CWE-113
Affected product: Hono
Published: 2026-05-28
Last modified: 2026-06-17

Description

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.21, the serialize() function in hono/cookie validates domain and path options against characters that corrupt Set-Cookie header syntax (;, \r, \n), but does not apply the same validation to sameSite and priority. An application that passes user-controlled input into either option may produce a Set-Cookie response header containing attacker-chosen additional attributes. This vulnerability is fixed in 4.12.21.

Frequently asked questions

What is CVE-2026-47675?: Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.21, the serialize() function in hono/cookie validates domain and path options against characters that corrupt Set-Cookie header syntax (;, \r, \n), but does not apply the same validation to sameSite and priority. An application that passes user-controlled input into either option may produce a Set-Cookie response header containing attacker-chosen additional attributes. This vulnerability is fixed in 4.12.21.
How severe is CVE-2026-47675?: CVE-2026-47675 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2026-47675 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-47675?: CVE-2026-47675 affects Hono. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-47675?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-47675 have an EU (EUVD) identifier?: Yes. CVE-2026-47675 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-32925.
When was CVE-2026-47675 published?: CVE-2026-47675 was published on 2026-05-28 and last updated on 2026-06-17.

References

https://github.com/honojs/hono/security/advisories/GHSA-3hrh-pfw6-9m5x

Affected products (1)

cpe:2.3:a:hono:hono:*:*:*:*:*:node.js:*:*

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