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CVE-2026-22818

MEDIUMCVSS 6.5/10EPSS 0.12%

Last modified

CVE-2026-22818 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.11.4, there is a flaw in Hono’s JWK/JWKS JWT verification middleware allowed the algorithm specified in the JWT header to influence signature verification when the selected JWK did not explicitly define an algorithm. EPSS estimates a 0.12% chance of exploitation in the next 30 days.

Description

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.11.4, there is a flaw in Hono’s JWK/JWKS JWT verification middleware allowed the algorithm specified in the JWT header to influence signature verification when the selected JWK did not explicitly define an algorithm. This could enable JWT algorithm confusion and, in certain configurations, allow forged tokens to be accepted. The JWK/JWKS JWT verification middleware has been updated to require an explicit allowlist of asymmetric algorithms when verifying tokens. The middleware no longer derives the verification algorithm from untrusted JWT header values. This vulnerability is fixed in 4.11.4.

Metrics

CVSS 3.1
6.5/10

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

EPSS Probability
0.12%

2.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
HonoHono< 4.11.4

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2026-22818?
Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.11.4, there is a flaw in Hono’s JWK/JWKS JWT verification middleware allowed the algorithm specified in the JWT header to influence signature verification when the selected JWK did not explicitly define an algorithm. This could enable JWT algorithm confusion and, in certain configurations, allow forged tokens to be accepted. The JWK/JWKS JWT verification middleware has been updated to require an explicit allowlist of asymmetric algorithms when verifying tokens. The middleware no longer derives the verification algorithm from untrusted JWT header values. This vulnerability is fixed in 4.11.4.
How severe is CVE-2026-22818?
CVE-2026-22818 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.12% probability of exploitation in the next 30 days.
How do I fix CVE-2026-22818?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-22818?

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Source: NVD / NIST