CVE-2026-44292

Description

protobufjs compiles protobuf definitions into JavaScript (JS) functions. Prior to 7.5.6 and 8.0.2, protobufjs generated message constructors copied enumerable properties from a provided properties object without filtering the __proto__ key. If an application constructed a message from an attacker-controlled plain object, an own enumerable __proto__ property could alter the prototype of that individual message instance. This vulnerability is fixed in 7.5.6 and 8.0.2.

CVSS v3.1 Score

5.3

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

EPSS — Exploit Prediction

0.0008

Probability of exploitation

0.24%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-1321 CWE-1321

Affected Products

Vendor	Product	Versions
protobufjs_project	protobufjs	< 7.5.6
protobufjs_project	protobufjs	8.0.0 — 8.0.2

References

Advisories & Patches

https://github.com/protobufjs/protobuf.js/security/advisories/GHSA-fx83-v9x8-x52w

Frequently Asked Questions

What is CVE-2026-44292? +

protobufjs compiles protobuf definitions into JavaScript (JS) functions. Prior to 7.5.6 and 8.0.2, protobufjs generated message constructors copied enumerable properties from a provided properties object without filtering the __proto__ key. If an application constructed a message from an attacker-controlled plain object, an own enumerable __proto__ property could alter the prototype of that individual message instance. This vulnerability is fixed in 7.5.6 and 8.0.2. It has a CVSS v3.1 base score of 5.3 (MEDIUM).

How severe is CVE-2026-44292? +

CVE-2026-44292 has a CVSS v3.1 score of 5.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0008, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-44292? +

CVE-2026-44292 affects products from protobufjs_project, specifically: protobufjs. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-44292? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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