{"id":"CVE-2026-44457","aliases":["GHSA-p77w-8qqv-26rm"],"url":"https://o3.security/vulnerability/CVE-2026-44457","summary":"Hono: Cache Middleware ignores Vary: Authorization / Vary: Cookie leading to cross-user cache leakage","details":"### Summary\n\nCache Middleware does not skip caching for responses that declare per-user variance via `Vary: Authorization` or `Vary: Cookie`. As a result, a response cached for one authenticated user may be served to subsequent requests from different users.\n\n### Details\n\nThe Cache Middleware skips caching when a response carries `Vary: *`, certain `Cache-Control` directives (`private`, `no-store`, `no-cache`), or `Set-Cookie`. However, `Vary: Authorization` and `Vary: Cookie` — the standard signals defined in RFC 9110 / RFC 9111 to indicate per-user responses — are not treated as cache-skip reasons.\n\nThis issue arises when applications use the Cache Middleware on endpoints that return user-specific data and rely on `Vary: Authorization` or `Vary: Cookie` to scope the response per user, without also setting `Cache-Control: private`.\n\n### Impact\n\nA user may receive a cached response that was originally generated for a different authenticated user. This may lead to:\n\n- Disclosure of personally identifiable information or other user-specific data present in the response body\n- Inconsistent or incorrect behavior in user-specific endpoints\n\nThis issue affects applications that use the Cache Middleware on endpoints whose responses vary by `Authorization` or `Cookie` and that do not also set `Cache-Control: private`.","published":"2026-05-13T14:58:52.931Z","modified":"2026-08-12T03:51:46.299864969Z","cvss":{"score":5.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"},"epss":{"score":0.00198,"percentile":0.09817,"asOf":"2026-08-14"},"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-2026-44457.json"},{"type":"ADVISORY","url":"https://github.com/honojs/hono/security/advisories/GHSA-p77w-8qqv-26rm"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-44457"},{"type":"PACKAGE","url":"https://github.com/honojs/hono"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:46.299864969Z"}}