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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
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Glexia's TakeAutomated analysiscritical

Security readout for executives and security teams

Plain-English summary

Affected protobuf.js applications may execute attacker-supplied JavaScript when decoding objects with a malicious protobuf definition. Successful exploitation could compromise application data, integrity, availability, and connected systems. Risk depends on whether an attacker can influence protobuf definitions, especially their type fields.

Executive priority

Prioritize immediate inventory and rapid patching for internet-facing or multi-tenant services that process externally influenced protobuf definitions. Other affected deployments still warrant urgent remediation because successful exploitation can provide arbitrary code execution with broad confidentiality, integrity, and availability impact.

Technical view

CVE-2026-41242 is a CWE-94 code-injection flaw in protobuf.js. The library compiles protobuf definitions into JavaScript functions without safely handling attacker-controlled type fields. A malicious definition can therefore execute arbitrary code during object decoding. Affected versions are below 7.5.5 and 8.0.0-experimental through 8.0.0.

Likely exposure

Highest exposure exists where applications load, generate, receive, or otherwise accept protobuf definitions from untrusted or lower-trust sources and then decode objects with them. Inventory direct and transitive protobuf.js dependencies. The supplied sources do not establish that ordinary messages decoded against fixed, trusted definitions are sufficient for exploitation.

Exploitation context

The issue is remotely reachable under the supplied CVSS assessment, requires low complexity and low privileges, and needs no user interaction. However, the bundle reports KEV as false and provides no evidence of active exploitation. Treat exploit activity as unconfirmed, not absent.

Researcher notes

The critical exposure condition is attacker influence over a definition's type fields followed by object decoding. Review schema-loading boundaries, tenant isolation, generated-definition pipelines, and transitive dependency resolution. The supplied commits document upstream changes, but this assessment does not infer exploit availability or additional affected products.

Mitigation direction

  • Upgrade the 7.x line to protobuf.js 7.5.5 or later.
  • Upgrade the 8.x experimental line to protobuf.js 8.0.1 or later.
  • Update lockfiles and rebuild deployed artifacts to prevent retaining vulnerable transitive versions.
  • Restrict protobuf definitions to trusted, controlled sources until upgrades are complete.
  • Consult applicable Red Hat advisories for packaged or vendor-managed deployments.

Validation and detection

  • Inspect manifests and lockfiles for direct and transitive protobuf.js versions.
  • Confirm every deployed artifact resolves protobuf.js outside the affected version ranges.
  • Trace whether applications accept or construct protobuf definitions from untrusted input.
  • Verify upgraded deployments use 7.5.5, 8.0.1, or a later compatible release.
  • Retest decoding workflows after upgrading, including rejected or malformed definitions.
Prepared
Confidence
high
Sources
7

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.

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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.

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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.

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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
14Source 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.

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