CVE-2026-54271: protobufjs-cli is the command line add-on for protobuf.js. Prior to 1.3.2 and 2.5.0, a previous fix for unsafe name handling in pbjs static / static-m...

Description

protobufjs-cli is the command line add-on for protobuf.js. Prior to 1.3.2 and 2.5.0, a previous fix for unsafe name handling in pbjs static / static-module code generation was incomplete. Affected versions of protobufjs-cli could still emit unsafe JavaScript references when generating static output from crafted JSON descriptor input. The common case of parsing schemas from .proto files is not affected. This is a bypass of CVE-2026-44295. An attacker who can provide or influence pre-parsed JSON descriptors passed to pbjs static code generation may be able to cause generated JavaScript output to contain attacker-controlled code. The injected code may execute if the generated file is later executed or imported and an affected generated API path is invoked. This vulnerability is fixed in 1.3.2 and 2.5.0.

Metrics

CVSS 3.1

8.2/10

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

EPSS Probability

0.23%

13.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-94

Affected Software

Vendor	Product	Versions
Protobufjs Project	Protobufjs-Cli	< 1.3.2
Protobufjs Project	Protobufjs-Cli	>= 2.0.0, < 2.5.0

References

https://github.com/protobufjs/protobuf.js/security/advisories/GHSA-pr59-h9ph-3fr8Mitigation, Vendor Advisory

Timeline

Published: Jun 22, 2026
Last Modified: Jun 24, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-54271?

protobufjs-cli is the command line add-on for protobuf.js. Prior to 1.3.2 and 2.5.0, a previous fix for unsafe name handling in pbjs static / static-module code generation was incomplete. Affected versions of protobufjs-cli could still emit unsafe JavaScript references when generating static output from crafted JSON descriptor input. The common case of parsing schemas from .proto files is not affected. This is a bypass of CVE-2026-44295. An attacker who can provide or influence pre-parsed JSON descriptors passed to pbjs static code generation may be able to cause generated JavaScript output to contain attacker-controlled code. The injected code may execute if the generated file is later executed or imported and an affected generated API path is invoked. This vulnerability is fixed in 1.3.2 and 2.5.0.

How severe is CVE-2026-54271?

CVE-2026-54271 has a CVSS score of 8.2/10 (HIGH severity). The EPSS model estimates a 0.23% probability of exploitation in the next 30 days.

How do I fix CVE-2026-54271?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.