{"id":"CVE-2026-54270","aliases":["GHSA-94rc-8x27-4472"],"url":"https://o3.security/vulnerability/CVE-2026-54270","summary":"protobufjs: Memory amplification from preserved unknown fields in binary decode","details":"protobufjs compiles protobuf definitions into JavaScript (JS) functions. From 8.2.0 to 8.4.2, protobufjs preserved unknown wire elements in message.$unknowns and did not provide a decode-time option to discard unknown fields before retaining them. A crafted protobuf payload containing many unknown fields could therefore cause a decoded message to retain substantially more memory than the input size would suggest, even when unknown-field round-tripping is not needed. protobufjs 8.5.0 added the relevant decode-time options, allowing applications that decode untrusted protobuf data to disable unknown-field retention during decode. protobufjs 8.6.2 flips the default so unknown fields are discarded unless explicitly opted into.","published":"2026-06-22T16:19:20.449Z","modified":"2026-08-12T03:51:12.065942777Z","cvss":{"score":5.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"},"epss":{"score":0.00402,"percentile":0.33069,"asOf":"2026-08-24"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"protobufjs","fixedVersion":"8.5.0"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54270.json"},{"type":"ADVISORY","url":"https://github.com/protobufjs/protobuf.js/security/advisories/GHSA-94rc-8x27-4472"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-54270"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:12.065942777Z"}}