Security readout for executives and security teams
Plain-English summary
CVE-2026-22818 affects Hono applications using its JWK/JWKS JWT verification middleware before version 4.11.4. In some configurations, a forged authentication token could be accepted because the middleware trusted the token’s own algorithm header when the JWK did not define one. This can undermine access controls for APIs and web applications.
Executive priority
Prioritize remediation for internet-facing APIs or services where JWTs control authentication or authorization. This is a high-severity authentication integrity issue with a published fix, but the provided sources do not show active exploitation.
Technical view
The issue is JWT algorithm confusion in Hono’s JWK/JWKS auth middleware. When a selected JWK lacked an explicit "alg", versions before 4.11.4 could derive the verification algorithm from the untrusted JWT header. The fix requires an explicit allowlist of asymmetric algorithms and stops using header.alg as the verification source. CWE-347 applies.
Likely exposure
Exposure is limited to applications running hono versions earlier than 4.11.4 that use the JWK/JWKS JWT verification middleware. Risk is highest where external identity provider keys or JWKS entries omit the "alg" field and JWTs gate sensitive API actions.
Exploitation context
The CVSS vector indicates network attackability, low complexity, no privileges, and no user interaction. The provided sources do not state active exploitation, and the CVE is not marked KEV. Practical impact depends on how the application configures JWT verification and key metadata.
Researcher notes
Focus review on Hono deployments using JWK/JWKS verification before 4.11.4. The key condition is a selected JWK without "alg", allowing untrusted JWT header algorithm influence. Avoid assuming exploitability in deployments using different middleware paths or already enforcing explicit algorithm allowlists.
Mitigation direction
- Upgrade hono to version 4.11.4 or later.
- Review Hono JWT middleware configuration for JWK/JWKS verification use.
- Require explicit allowed asymmetric algorithms for token verification.
- Check vendor advisory for any updated configuration guidance.
Validation and detection
- Inventory applications and dependencies for hono versions earlier than 4.11.4.
- Identify routes using Hono JWK or JWKS JWT verification middleware.
- Review JWKS/JWK metadata for keys missing explicit "alg" values.
- Confirm upgraded middleware no longer derives verification algorithm from JWT header values.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-347: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2026-22818 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.2 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N3.94.2Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.2HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/honojs/hono/security/advisories/GHSA-3vhc-576x-3qv4CVE reference · x_refsource_CONFIRM
- https://github.com/honojs/hono/commit/190f6e28e2ca85ce3d1f2f54db1310f5f3eab134CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Verification of Cryptographic Signature
Improper Verification of Cryptographic Signature represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.