{"id":"CVE-2026-55451","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-55451","generatedAt":"2026-10-28T01:47:30.892Z","title":"When an application converts untrusted PO or i18next translation data, a __proto__ segment resolves Object.prototype as the nested write target and Object.assign writes attacker-controlled translated properties onto the process-wide prototype.","description":"gettext-converter provides gettext resource conversion utilities for JavaScript. Prior to 1.3.3, js2i18next() in lib/js2i18next.js splits nested translation keys using options.keyseparator, whose default value consists of two number signs, and uses each segment as a dynamic object key without rejecting __proto__, constructor, or prototype. When an application converts untrusted PO or i18next translation data, a __proto__ segment resolves Object.prototype as the nested write target and Object.assign writes attacker-controlled translated properties onto the process-wide prototype. The resulting prototype pollution can cause denial of service and may enable application-dependent follow-on attacks. This issue is fixed in version 1.3.3.","published":"2026-09-14T17:17:48.000Z","lastModified":"2026-09-30T19:57:08.000Z","status":"Deferred","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"4.0","score":8.3,"severity":"HIGH","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/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/M"},"cwe":["CWE-1321"],"affected":[],"epss":{"score":0.00566,"percentile":0.46701,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.57%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://github.com/locize/gettext-converter/commit/df90c3b93e51faef68891d97b626544f619c5b31","source":"security-advisories@github.com"},{"url":"https://github.com/locize/gettext-converter/issues/15","source":"security-advisories@github.com"},{"url":"https://github.com/locize/gettext-converter/releases/tag/v1.3.3","source":"security-advisories@github.com"},{"url":"https://github.com/locize/gettext-converter/security/advisories/GHSA-f4jp-rw7w-ccwg","source":"security-advisories@github.com"},{"url":"https://github.com/locize/gettext-converter/issues/15","source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-55451","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}