protobufjs compiles protobuf definitions into JavaScript (JS) functions. Prior to 7.5.6 and 8.0.2, protobufjs used plain objects with inherited prototypes for internal type lookup tables used by generated encode and decode functions. If Object.prototype had already been polluted, those lookup tables could resolve attacker-controlled inherited properties as valid protobuf type information. This could cause attacker-controlled strings to be emitted into generated JavaScript code. This vulnerability is fixed in 7.5.6 and 8.0.2.
protobufjs compiles protobuf definitions into JavaScript (JS) functions. Prior to 7.5.6 and 8.0.2, protobufjs used plain objects with inherited prototypes for internal type lookup tables used by generated encode and decode functions. If Object.prototype had already been polluted, those lookup tables could resolve attacker-controlled inherited properties as valid protobuf type information. This could cause attacker-controlled strings to be emitted into generated JavaScript code. This vulnerability is fixed in 7.5.6 and 8.0.2.
protobufjs compiles protobuf definitions into JavaScript (JS) functions. Prior to 7.5.6 and 8.0.2, protobufjs used plain objects with inherited prototypes for internal type lookup tables used by generated encode and decode functions. If Object.prototype had already been polluted, those lookup tables could resolve attacker-controlled inherited properties as valid protobuf type information. This could cause attacker-controlled strings to be emitted into generated JavaScript code. This vulnerability is fixed in 7.5.6 and 8.0.2.
## Summary
protobufjs used plain objects with inherited prototypes for internal type lookup tables used by generated encode and decode functions. If `Object.prototype` had already been polluted, those lookup tables could resolve attacker-controlled inherited properties as valid protobuf type information.
This could cause attacker-controlled strings to be emitted into generated JavaScript code.
## Impact
An attacker who can first trigger a prototype pollution vulnerability may be able to influence generated protobufjs encode or decode functions in a way that can lead to arbitrary JavaScript execution.
This issue requires a separate prototype pollution primitive before protobufjs is invoked.
Applications without a reachable prototype pollution primitive are not directly exploitable through this issue alone.
## Preconditions
- The application or one of its dependencies must allow an attacker to pollute `Object.prototype`.
- The polluted property must affect protobufjs internal type lookup behavior.
- The application must use protobufjs functionality that generates encode or decode code for affected types.
- The generated code path must be reached after the prototype pollution has occurred.
## Workarounds
Avoid running affected versions in applications where attacker-controlled input can pollute `Object.prototype`. If immediate upgrade is not possible, remove or mitigate reachable prototype pollution primitives and isolate schema/message processing from untrusted application state.
EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.
Original publisher date fields
datePublished: May 13, 2026, 2:42:13 PM
dateUpdated: May 13, 2026, 3:32:06 PM
4 related source bulletins · separate from aliases
RHSA-2026:42815: Red Hat Security Advisory: Red Hat Ansible Automation Platform 2.2 security update
WID-SEC-W-2026-2452: Red Hat Ansible Automation Platform (node-tar, linkify-it, protobufjs, brace-expansion, fast-uri, DOMPurify): Mehrere Schwachstellen
No normalized affected-package data is projected for this source revision. The original publisher record may contain additional product and version evidence; this does not establish that a package is unaffected.
NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.
The original JSON retains the logical configuration operators, exclusions and version bounds.
No normalized affected-package data is projected for this source revision. The original publisher record may contain additional product and version evidence; this does not establish that a package is unaffected.