CVE-2026-41242Public exploitNetwork attack vector

Code execution via unsanitized schema type names

Published Apr 18, 2026 · Updated Apr 18, 2026

Code injection in protobuf.js before 7.5.5 and 8.0.0-experimental through 8.0.0 allows remote authenticated users to execute JavaScript. The Type constructor accepts schema-controlled names unchanged, allowing punctuation from a crafted JSON descriptor to enter generated Function code during decoding. Exploitation requires an application to load an attacker-influenced schema through reflection APIs and reach generated code; trusted, application-defined schemas are not exposed.

CVSS severity9.4
Critical
EPSS probability0.77%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Code injection in protobuf.js before 7.5.5 and 8.0.0-experimental through 8.0.0 allows remote authenticated users to execute JavaScript. The Type constructor accepts schema-controlled names unchanged, allowing punctuation from a crafted JSON descriptor to enter generated Function code during decoding. Exploitation requires an application to load an attacker-influenced schema through reflection APIs and reach generated code; trusted, application-defined schemas are not exposed.

The record

CVE
CVE-2026-41242
Published
Apr 18, 2026
Updated
Apr 18, 2026
Vendor
protobufjs
Product
protobuf.js
Classifications
CWE-94, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 18, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 7.5.5
  2. Affected versionversion=>= 8.0.0-experimental, < 8.0.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

protobufjs · protobuf.jsversion=< 7.5.5; version=>= 8.0.0-experimental, < 8.0.1

Published CVSS scores

9.4GitHub Advisory DatabaseCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')
T1059.007JavaScript/JScript

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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