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CVE-2026-44291

HIGHCVSS 8.1/10EPSS 0.50%

Last modified

CVE-2026-44291 is a high-severity vulnerability rated 8.1/10 on the CVSS scale. 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. EPSS estimates a 0.50% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1
8.1/10

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

EPSS Probability
0.50%

38.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
Protobufjs ProjectProtobufjs< 7.5.6
Protobufjs ProjectProtobufjs>= 8.0.0, < 8.0.2

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2026-44291?
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.
How severe is CVE-2026-44291?
CVE-2026-44291 has a CVSS score of 8.1/10 (HIGH severity). The EPSS model estimates a 0.50% probability of exploitation in the next 30 days.
How do I fix CVE-2026-44291?
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.

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Source: NVD / NIST