CVE-2021-21368

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Summary

CVECVE-2021-21368
StatePUBLIC
Assigner[email protected]
Source PriorityCVE Program / NVD first with legacy fallback
Published2021-03-12 17:15:00 UTC
Updated2022-10-24 17:11:00 UTC
Descriptionmsgpack5 is a msgpack v5 implementation for node.js and the browser. In msgpack5 before versions 3.6.1, 4.5.1, and 5.2.1 there is a "Prototype Poisoning" vulnerability. When msgpack5 decodes a map containing a key "__proto__", it assigns the decoded value to __proto__. Object.prototype.__proto__ is an accessor property for the receiver's prototype. If the value corresponding to the key __proto__ decodes to an object or null, msgpack5 sets the decoded object's prototype to that value. An attacker who can submit crafted MessagePack data to a service can use this to produce values that appear to be of other types; may have unexpected prototype properties and methods (for example length, numeric properties, and push et al if __proto__'s value decodes to an Array); and/or may throw unexpected exceptions when used (for example if the __proto__ value decodes to a Map or Date). Other unexpected behavior might be produced for other types. There is no effect on the global prototype. This "prototype poisoning" is sort of a very limited inversion of a prototype pollution attack. Only the decoded value's prototype is affected, and it can only be set to msgpack5 values (though if the victim makes use of custom codecs, anything could be a msgpack5 value). We have not found a way to escalate this to true prototype pollution (absent other bugs in the consumer's code). This has been fixed in msgpack5 version 3.6.1, 4.5.1, and 5.2.1. See the referenced GitHub Security Advisory for an example and more details.

Risk And Classification

Problem Types: CWE-1321

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Msgpack5 Project Msgpack5 All All All All

References

ReferenceSourceLinkTags
Merge pull request from GHSA-gmjw-49p4-pcfm · mcollina/msgpack5@d4e6cb9 · GitHub MISC github.com Patch, Third Party Advisory
Release v4.5.1 · mcollina/msgpack5 · GitHub MISC github.com Release Notes, Third Party Advisory
msgpack5 MISC www.npmjs.com Product, Third Party Advisory
Release v3.6.1 · mcollina/msgpack5 · GitHub MISC github.com Release Notes, Third Party Advisory
Release v5.2.1 · mcollina/msgpack5 · GitHub MISC github.com Release Notes, Third Party Advisory
Prototype poisoning · Advisory · mcollina/msgpack5 · GitHub CONFIRM github.com Exploit, Third Party Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Legacy QID Mappings

  • 982906 Nodejs (npm) Security Update for msgpack5 (GHSA-gmjw-49p4-pcfm)

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