CVE-2026-54270: medium-severity vulnerability in protobufjs protobuf.js
protobufjs: Memory amplification from preserved unknown fields in binary decode
Published · Updated
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.3epss 0.4%
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Affected products
protobufjs · protobuf.jsRelated CVEs — protobufjs protobuf.js
In the same product, most dangerous first.
CVE-2026-41242CRITICALprotobufjs has an arbitrary code execution issueEPSS 0.8%CVE-2026-44289HIGHprotobufjs: Denial of service through unbounded protobuf recursionEPSS 0.6%CVE-2026-44291HIGHprotobufjs: Code generation gadget after prototype pollutionEPSS 0.5%CVE-2026-48712HIGHprotobufjs: Denial of service through unbounded Any expansion during JSON conversionEPSS 0.5%CVE-2026-44294MEDIUMprotobufjs: Denial of service from crafted field names in generated codeEPSS 0.4%CVE-2026-44293HIGHprotobufjs: Code injection through bytes field defaults in generated toObject codeEPSS 0.4%