LiveActive security incident?Get immediate response
CVE Record

CVE-2026-41242: protobufjs has an arbitrary code execution issue

protobufjs compiles protobuf definitions into JavaScript (JS) functions. In versions prior to 8.0.1 and 7.5.5, attackers can inject arbitrary code in the "type" fields of protobuf definitions, which will then execute during object decoding using that definition. Versions 8.0.1 and 7.5.5 patch the issue.

CriticalCVSS 9.4Not KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysiscritical

Security readout for executives and security teams

Plain-English summary

protobuf.js can turn protobuf definitions into JavaScript code. In vulnerable versions, a malicious definition can place code in a type field and have it run when data is decoded. This is critical for systems that load protobuf definitions from users, partners, plugins, or other less-trusted sources.

Executive priority

Treat as urgent where protobuf definitions cross trust boundaries. Prioritize internet-facing, multi-tenant, plugin-based, and partner-integrated systems first. Where definitions are fully static and controlled, risk may be lower, but dependency remediation should still be scheduled promptly.

Technical view

CVE-2026-41242 is CWE-94 arbitrary code execution in protobuf.js before 7.5.5 and experimental 8.0.0 builds before 8.0.1. The issue is in generated JavaScript functions: attacker-controlled protobuf definition type fields may execute during object decoding. CVSS v4.0 is 9.4.

Likely exposure

Exposure is most likely in JavaScript applications or products using protobuf.js that compile or load protobuf definitions dynamically, especially from untrusted or semi-trusted sources. Projects may also be exposed through transitive dependencies or vendor packages that bundle vulnerable protobuf.js versions.

Exploitation context

The source bundle does not show CISA KEV listing or confirmed active exploitation. The advisory states exploitation requires the attacker to inject arbitrary code into protobuf definition type fields, with execution occurring during decoding using that definition.

Researcher notes

The key exposure question is whether an attacker can influence protobuf definitions, not merely protobuf message data. The provided sources identify fixed versions and patches, but do not provide evidence of active exploitation. Avoid assuming impact in products without confirming protobuf.js version and definition-loading behavior.

Mitigation direction

  • Upgrade protobuf.js to 7.5.5 or 8.0.1 as applicable.
  • Inventory direct and transitive protobuf.js dependencies in application lockfiles and SBOMs.
  • Avoid loading untrusted protobuf definitions until patched and validated.
  • Review Red Hat advisories if consuming affected Red Hat-packaged components.
  • Monitor the GitHub advisory and vendor errata for updated guidance.

Validation and detection

  • Confirm deployed builds resolve protobuf.js 7.5.5, 8.0.1, or later.
  • Search code paths that parse, load, or compile protobuf definitions dynamically.
  • Check whether protobuf definitions can be supplied by users, tenants, plugins, or partners.
  • Verify CI dependency scans flag protobuf.js versions below fixed releases.
  • Confirm container images and packaged products include the remediated dependency.
Prepared
Confidence
high
Sources
12

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · medium confidence lookup

CWE-94: Code execution behavior lookup

Code execution and unsafe deserialization weaknesses often justify reviewing execution behavior and process telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
description · low confidence lookup

Execution behavior lookup

The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2026-41242 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
Critical
CVSS
9.4 (4.0)
Known Exploited
No
Published

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
5Timeline events
2ADP providers
13Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: pocAutomatable: yesTechnical Impact: total

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
9.4CVSS 4.0CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H——GitHub_M
8.8CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H2.85.9redhat-SADP

Vulnerability scoring details

Base CVSS 4.0 score

9.4Critical
CVSS 4.0 vector shape for CVE-2026-41242Attack VectorAttack ComplexityAttack RequirementsPrivileges RequiredUser InteractionVS ConfidentialityVS IntegrityVS AvailabilitySS ConfidentialitySS IntegritySS Availability

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Attack Requirements
NonePresent
Privileges Required
NoneLowHigh
User Interaction
NonePassiveActive
VS Confidentiality
HighLowNone
VS Integrity
HighLowNone
VS Availability
HighLowNone
SS Confidentiality
HighLowNone
SS Integrity
HighLowNone
SS Availability
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Made public.

  3. CVE publishedCVE Program

    The CVE record was published.

  4. ADP timelineredhat-SADP

    Reported to Red Hat.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
redhat-SADPprotobufjs: protobufjs: Arbitrary code execution via injected protobuf definition type fields
other:Red Hat severity ratingcvssV3_1
  • 2026-04-18T17:00:50.677Z: Reported to Red Hat.
  • 2026-04-18T16:18:10.652Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
protobufjsprotobuf.js< 7.5.5, >= 8.0.0-experimental, < 8.0.1Listed
Weakness

CWE details

CWE-94

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-94 · source CWE mapping

Improper Control of Generation of Code ('Code Injection')

Improper Control of Generation of Code ('Code Injection') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs