Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') Affecting librechat package, versions <0.8.7-r5


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.22% (13th percentile)

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  • Snyk IDSNYK-CHAINGUARDLATEST-LIBRECHAT-18481504
  • published31 Jul 2026
  • disclosed8 Jul 2026

Introduced: 8 Jul 2026

CVE-2026-59876  (opens in a new tab)
CWE-1321  (opens in a new tab)

How to fix?

Upgrade Chainguard librechat to version 0.8.7-r5 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream librechat package and not the librechat package as distributed by Chainguard. See How to fix? for Chainguard relevant fixed versions and status.

protobufjs compiles protobuf definitions into JavaScript (JS) functions. From 8.2.0 until 8.6.5, the protobufjs Text Format extension parsed string-keyed map entries using ordinary property assignment, allowing a map entry with key proto to change the prototype of the returned map object instead of creating an own map entry in protobufjs/ext/textformat. This issue is fixed in version 8.6.5.

CVSS Base Scores

version 3.1