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CVE Record

CVE-2026-44293: protobufjs: Code injection through bytes field defaults in generated toObject code

protobufjs compiles protobuf definitions into JavaScript (JS) functions. Prior to 7.5.6 and 8.0.2, protobufjs generated JavaScript for toObject conversion could include an unsafe expression derived from a schema-controlled bytes field default value. A crafted descriptor with a non-string default value for a bytes field could cause attacker-controlled code to be emitted into the generated conversion function. This vulnerability is fixed in 7.5.6 and 8.0.2.

HighCVSS 7.7Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A malicious protobuf descriptor can make vulnerable protobuf.js versions generate and run attacker-controlled JavaScript during object conversion. Successful exploitation could compromise the application process and its data. Exposure depends on an attacker being able to influence schema or descriptor content, including a non-string default for a bytes field.

Executive priority

Prioritize remediation for internet-facing or multi-tenant services that accept externally influenced protobuf definitions. Treat other affected deployments as a scheduled high-priority upgrade. The potential impact is process-level code execution, but the documented preconditions make this less urgent than an unauthenticated, broadly exploited vulnerability.

Technical view

CVE-2026-44293 is a CWE-94 code-injection flaw in protobuf.js toObject code generation. A crafted descriptor containing a bytes field with a non-string default can place an unsafe expression into generated JavaScript. The affected ranges are below 7.5.6 and 8.0.0 through 8.0.1; fixes are available in 7.5.6 and 8.0.2.

Likely exposure

Highest risk exists where applications load, compile, or otherwise process protobuf descriptors influenced by untrusted or lower-trust users. Applications using affected versions only with fixed, trusted schemas have a reduced attack path, but should still upgrade. Dependency inventories must account for transitive and bundled copies.

Exploitation context

The CVSS 4.0 score is 7.7 with network reachability, low complexity, low privileges, no user interaction, and high confidentiality, integrity, and availability impacts. Attack preparation is required. The supplied sources do not identify CISA KEV listing or report active exploitation.

Researcher notes

Assessment should trace descriptor provenance, not merely protobuf message provenance. The critical condition is a schema-controlled bytes default represented as a non-string value reaching toObject JavaScript generation. The supplied record establishes the vulnerable behavior and fixed versions, but provides no evidence of exploitation in the wild or details about affected downstream products beyond referenced Red Hat advisories.

Mitigation direction

  • Upgrade protobuf.js versions below 7.5.6 to version 7.5.6 or later.
  • Upgrade protobuf.js 8.0.0 or 8.0.1 to version 8.0.2 or later.
  • Prevent untrusted parties from supplying or modifying protobuf schemas and descriptors.
  • Review applicable Red Hat advisories when protobuf.js arrives through Red Hat-packaged products.

Validation and detection

  • Inventory direct, transitive, bundled, and vendored protobuf.js versions across production and build environments.
  • Confirm no deployed instance is below 7.5.6 or within versions 8.0.0 through 8.0.1.
  • Identify workflows that compile descriptors or invoke generated toObject conversion logic.
  • Verify schema and descriptor sources are trusted, authenticated, and protected against unauthorized modification.
  • Rebuild and redeploy artifacts after upgrading, then confirm runtime dependency versions.
Prepared
Confidence
high
Sources
6

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
cve · low confidence lookup

CVE-2026-44293 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
High
CVSS
7.7 (4.0)
Known Exploited
No
Published

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

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
16Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical 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
7.7CVSS 4.0HighCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N——GitHub_M
7.1CVSS 3.1HighCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:H1.65.5redhat-SADP

Vulnerability scoring details

Base CVSS 4.0 score

7.7High
CVSS 4.0 vector shape for CVE-2026-44293Attack VectorAttack ComplexityAttack RequirementsPrivileges RequiredUser InteractionVS ConfidentialityVS IntegrityVS AvailabilitySS ConfidentialitySS IntegritySS Availability

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

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 due to unsafe expression generation from crafted protobuf descriptors
other:Red Hat severity ratingcvssV3_1
  • 2026-05-13T16:03:50.961Z: Reported to Red Hat.
  • 2026-05-13T14:43:33.342Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
protobufjsprotobuf.js< 7.5.6, >= 8.0.0, < 8.0.2Listed
Weakness

CWE details

CWE-94

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