{"id":"CVE-2026-44459","aliases":["GHSA-hm8q-7f3q-5f36"],"url":"https://o3.security/vulnerability/CVE-2026-44459","summary":"Hono: Improper validation of NumericDate claims (exp, nbf, iat) in JWT verify()","details":"### Summary\n\nImproper validation of the JWT NumericDate claims `exp`, `nbf`, and `iat` in `hono/utils/jwt` allows tokens with non-spec-compliant claim values to silently bypass time-based checks. This issue is not exploitable by an anonymous attacker; it only manifests when a malformed claim value reaches `verify()` — typically when the application itself issues such tokens, or when the signing key is otherwise under attacker control.\n\n### Details\n\nThe validation routine combined option, presence, and threshold checks in a single short-circuiting expression, so several classes of malformed values were silently skipped instead of rejected:\n\n- A falsy numeric value short-circuited the presence check.\n- A non-finite numeric value compared as never-after-now and never-expired.\n- A non-numeric type produced NaN comparisons that evaluated false.\n\nThis deviates from RFC 7519 §4.1.4, which defines NumericDate as a finite JSON numeric value.\n\n### Impact\n\nAn actor able to issue tokens accepted by the application may craft tokens whose `exp`, `nbf`, or `iat` claims silently bypass time-based enforcement. This may lead to:\n\n- Tokens treated as never expiring even with `exp` configured on the verifier.\n- Tokens with a future `nbf` accepted as currently valid.\n- Tokens with a future `iat` accepted as legitimately issued.\n\nDeployments using a well-formed token issuer and protecting the signing key are not affected.","published":"2026-05-13T15:02:23.872Z","modified":"2026-08-12T03:51:47.611531957Z","cvss":{"score":3.8,"severity":"LOW","vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N"},"epss":{"score":0.00216,"percentile":0.12317,"asOf":"2026-08-15"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"hono","fixedVersion":"4.12.18"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44459.json"},{"type":"ADVISORY","url":"https://github.com/honojs/hono/security/advisories/GHSA-hm8q-7f3q-5f36"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-44459"},{"type":"PACKAGE","url":"https://github.com/honojs/hono"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:47.611531957Z"}}