High severity · published May 13, 2026
CVE-2026-44291
protobufjs: Code generation gadget after prototype pollution
8.1
CVSS
0.5%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 43% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
PR
protobuf.js · protobufjs
< 7.5.6; >= 8.0.0, < 8.0.2 · source: vendor
PR
Protobufjs · Protobufjs Project
before 7.5.6; 8.0.0 before 8.0.2 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-44291
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-44291
Mitigation
https://github.com/protobufjs/protobuf.js/security/advisories/GHSA-75px-5xx7-5xc7
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