{"id":"CVE-2025-71381","aliases":["EUVD-2025-210393","GHSA-cw3j-28qq-x3xh","GHSA-q7jf-gf43-6x6p"],"status":"published","title":"Hono - Vary Header Injection in CORS Middleware","description":"Hono before 4.10.3 contains a flaw in its CORS middleware: when the origin is not set to \"*\", the middleware copies the Vary header from the incoming request into the response. Because Vary is a response header that should be managed by the server, an attacker can supply arbitrary Vary values that are reflected into the response, potentially causing cache key pollution and inconsistent CORS enforcement in environments that rely on shared caches or proxies.","severity":{"version":"4.0","score":6.9,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00292,"percentile":0.22069,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-113","CWE-444"],"published":"2025-10-24T19:15:13Z","modified":"2026-10-31T02:47:29Z","fixes":[{"ecosystem":"npm","package":"hono","fixed_in":["4.10.3"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"hono","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.10.3"}]}]},{"source":"osv","ecosystem":"npm","package":"hono","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"4.10.3"}]}]}],"products":[{"vendor":"hono","product":"hono"},{"vendor":"honojs","product":"hono"}],"references":[{"url":"https://github.com/honojs/hono/security/advisories/GHSA-q7jf-gf43-6x6p","tags":["vendor-advisory","advisory","web"]},{"url":"https://www.vulncheck.com/advisories/hono-vary-header-injection-in-cors-middleware","tags":["third-party-advisory","advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2025-71381","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-cw3j-28qq-x3xh"},{"url":"https://github.com/honojs/hono/commit/d9b8b4b73b4f997994f2764013207365fe711282","tags":["web"]},{"url":"https://github.com/advisories/GHSA-q7jf-gf43-6x6p"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/71xxx/CVE-2025-71381.json","tags":["advisory"]},{"url":"https://github.com/honojs/hono","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2025-71381","title":"Hono - Vary Header Injection in CORS Middleware","description":"Hono before 4.10.3 contains a flaw in its CORS middleware: when the origin is not set to \"*\", the middleware copies the Vary header from the incoming request into the response. Because Vary is a response header that should be managed by the server, an attacker can supply arbitrary Vary values that are reflected into the response, potentially causing cache key pollution and inconsistent CORS enforcement in environments that rely on shared caches or proxies.","status":"published","published":"2026-06-30T22:08:21.523Z","modified":"2026-10-29T21:15:18.744Z","cvss":[{"version":"4.0","score":6.9,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N","level":"medium","assessor":"cna"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-113"],"updated_at":"2026-11-02T14:32:42.751171Z"}],"euvd":[{"id":"EUVD-2025-210393","description":"Hono before 4.10.3 contains a flaw in its CORS middleware: when the origin is not set to \"*\", the middleware copies the Vary header from the incoming request into the response. Because Vary is a response header that should be managed by the server, an attacker can supply arbitrary Vary values that are reflected into the response, potentially causing cache key pollution and inconsistent CORS enforcement in environments that rely on shared caches or proxies.","status":"published","published":"2026-06-30T22:08:21Z","modified":"2026-10-29T21:15:18Z","cvss":[{"version":"4.0","score":6.9,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N","level":"medium"}],"updated_at":"2026-11-02T16:59:14.250155Z"}],"ghsa":[{"id":"GHSA-cw3j-28qq-x3xh","title":"Duplicate Advisory: Hono vulnerable to Vary Header Injection leading to potential CORS Bypass","description":"## Duplicate Advisory\n\nThis advisory has been withdrawn because it is a duplicate of GHSA-q7jf-gf43-6x6p. This link is maintained to preserve external references.\n\n## Original Description\nHono before 4.10.2 (fixed in 4.10.3) contains a flaw in its CORS middleware: when the origin is not set to \"*\", the middleware copies the Vary header from the incoming request into the response. Because Vary is a response header that should be managed by the server, an attacker can supply arbitrary Vary values that are reflected into the response, potentially causing cache key pollution and inconsistent CORS enforcement in environments that rely on shared caches or proxies.","status":"withdrawn","published":"2026-07-01T00:34:02Z","modified":"2026-10-02T18:28:40Z","cvss":[{"version":"4.0","score":6.9,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","level":"medium"}],"cwes":["CWE-113"],"updated_at":"2026-11-02T14:41:24.739884Z"},{"id":"GHSA-q7jf-gf43-6x6p","title":"Hono vulnerable to Vary Header Injection leading to potential CORS Bypass","description":"### Summary  \nA flaw in the CORS middleware allowed request `Vary` headers to be reflected into the response, enabling attacker-controlled `Vary` values and potentially affecting cache behavior.\n\n### Details  \nThe middleware previously copied the `Vary` header from the request when `origin` was not set to `\"*\"`.  Since `Vary` is a response header that should only be managed by the server, this could allow an attacker to influence caching behavior or cause inconsistent CORS handling.\n\nMost environments will see impact only when shared caches or proxies rely on the `Vary` header. The practical effect varies by configuration.\n\n### Impact  \nMay cause cache key pollution and inconsistent CORS enforcement in certain setups. No direct confidentiality, integrity, or availability impact in default configurations.  \n\n### Resolution  \nUpdate to the latest patched release. The CORS middleware has been corrected to handle `Vary` exclusively as a response header.","status":"published","published":"2025-10-24T19:15:13Z","modified":"2026-10-02T18:28:56Z","cvss":[{"version":"3.1","score":4.2,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N","level":"medium"}],"cwes":["CWE-444"],"updated_at":"2026-11-02T14:41:24.739884Z"}],"nvd":[{"id":"CVE-2025-71381","description":"Hono before 4.10.3 contains a flaw in its CORS middleware: when the origin is not set to \"*\", the middleware copies the Vary header from the incoming request into the response. Because Vary is a response header that should be managed by the server, an attacker can supply arbitrary Vary values that are reflected into the response, potentially causing cache key pollution and inconsistent CORS enforcement in environments that rely on shared caches or proxies.","status":"published","published":"2026-06-30T23:16:52.027Z","modified":"2026-10-29T21:17:05.513Z","cvss":[{"version":"4.0","score":6.9,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium","assessor":"secondary"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-113"],"updated_at":"2026-11-02T14:12:02.535029Z"}],"osv":[{"id":"CVE-2025-71381","title":"Hono - Vary Header Injection in CORS Middleware","description":"Hono before 4.10.3 contains a flaw in its CORS middleware: when the origin is not set to \"*\", the middleware copies the Vary header from the incoming request into the response. Because Vary is a response header that should be managed by the server, an attacker can supply arbitrary Vary values that are reflected into the response, potentially causing cache key pollution and inconsistent CORS enforcement in environments that rely on shared caches or proxies.","status":"published","published":"2026-06-30T22:08:21.523Z","modified":"2026-10-31T02:47:29.41908366Z","cvss":[{"version":"4.0","score":6.9,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N","level":"medium"}],"cwes":["CWE-113"],"updated_at":"2026-11-02T15:44:53.185592Z"},{"id":"GHSA-cw3j-28qq-x3xh","title":"Duplicate Advisory: Hono vulnerable to Vary Header Injection leading to potential CORS Bypass","description":"## Duplicate Advisory\n\nThis advisory has been withdrawn because it is a duplicate of GHSA-q7jf-gf43-6x6p. This link is maintained to preserve external references.\n\n## Original Description\nHono before 4.10.2 (fixed in 4.10.3) contains a flaw in its CORS middleware: when the origin is not set to \"*\", the middleware copies the Vary header from the incoming request into the response. Because Vary is a response header that should be managed by the server, an attacker can supply arbitrary Vary values that are reflected into the response, potentially causing cache key pollution and inconsistent CORS enforcement in environments that rely on shared caches or proxies.","status":"withdrawn","published":"2026-07-01T00:34:02Z","modified":"2026-10-02T18:45:04.878855206Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","level":"medium"},{"version":"4.0","score":6.9,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium"}],"cwes":["CWE-113"],"updated_at":"2026-11-02T15:46:45.639885Z"},{"id":"GHSA-q7jf-gf43-6x6p","title":"Hono vulnerable to Vary Header Injection leading to potential CORS Bypass","description":"### Summary  \nA flaw in the CORS middleware allowed request `Vary` headers to be reflected into the response, enabling attacker-controlled `Vary` values and potentially affecting cache behavior.\n\n### Details  \nThe middleware previously copied the `Vary` header from the request when `origin` was not set to `\"*\"`.  Since `Vary` is a response header that should only be managed by the server, this could allow an attacker to influence caching behavior or cause inconsistent CORS handling.\n\nMost environments will see impact only when shared caches or proxies rely on the `Vary` header. The practical effect varies by configuration.\n\n### Impact  \nMay cause cache key pollution and inconsistent CORS enforcement in certain setups. No direct confidentiality, integrity, or availability impact in default configurations.  \n\n### Resolution  \nUpdate to the latest patched release. The CORS middleware has been corrected to handle `Vary` exclusively as a response header.","status":"published","published":"2025-10-24T19:15:13Z","modified":"2026-10-02T18:45:04.883415459Z","cvss":[{"version":"3.1","score":4.2,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N","level":"medium"}],"cwes":["CWE-444"],"updated_at":"2026-11-02T15:46:54.055966Z"}]}}