How severe is CVE-2026-44294?

CVE-2026-44294 has a CVSS score of 5.3/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2026-44294?

CVE-2026-44294 affects the following packages: protobufjs (npm), protobufjs (npm). Ecosystems affected: npm.

How do I fix CVE-2026-44294?

Update protobufjs to 7.5.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-44294 is resolved across your whole dependency graph.

How do I detect CVE-2026-44294 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for protobufjs, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-44294 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is CVE-2026-44294 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-44294 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-44294?

CVE-2026-44294 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 38th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-44294?

CVE-2026-44294 is classified as Improper Input Validation (CWE-20). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-44294 published, and has it been updated?

CVE-2026-44294 was published on May 13, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦

📦 npm

Not in CISA KEV

MEDIUM severity

CVE-2026-44294 — protobufjs

MEDIUM

CVE-2026-44294 is a medium-severity (CVSS 5.3) Improper Input Validation vulnerability in protobufjs. A fix is available for protobufjs — see the affected versions and patch details below.

protobufjs: Denial of service from crafted field names in generated code

Also known asGHSA-2pr8-phx7-x9h3

Published

May 13, 2026

Updated

Oct 28, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-44294.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs38th percentile — riskier than 38% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

2 pkgs affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

6Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream

protobufjsnpm

122.9Mdownloads / week

Description

Summary

protobufjs generated JavaScript property accessors from schema-controlled field and oneof names. Certain control characters in field names were not escaped before being embedded into generated function bodies. A crafted schema or JSON descriptor could therefore cause generated encode, decode, verify, or conversion functions to fail during compilation.

Impact

An attacker who can provide or influence a protobuf schema or JSON descriptor may be able to make affected message types unusable by causing protobufjs runtime code generation to throw a syntax error.

This is a denial of service issue for applications that load untrusted schemas or descriptors. Applications that only use trusted, application-defined schemas are not directly affected by this issue.

The issue is not known to allow code execution by itself.

Preconditions

The application must allow an attacker to control or influence a protobuf schema or JSON descriptor.
The crafted input must define a field name containing control characters that reach generated JavaScript property access.
The application must perform an operation that triggers protobufjs code generation for the affected type, such as encode, decode, verify, fromObject, or toObject.

Workarounds

Do not load protobuf schemas or JSON descriptors from untrusted sources with affected versions. If untrusted schemas must be accepted, validate field names before loading them and reject names containing control characters.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`protobufjs`	all versions	7.5.6`npm install protobufjs@7.5.6`
📦npm	`protobufjs`	≥ 8.0.0&&< 8.0.2	8.0.2`npm install protobufjs@8.0.2`

Affected Products

1 product · 2 configurations

Application

protobufjsprotobufjs_project

≥ 8.0.0 && < 8.0.2

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for protobufjs, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update protobufjs to 7.5.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-44294 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

This is an Moderate denial of service flaw in protobufjs, which arises from improper escaping of control characters in field names during JavaScript property accessor generation. A remote attacker could exploit this by providing a specially crafted schema or JSON descriptor, leading to compilation failure and a denial…

Workaround published by Red Hat

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Source: Red Hat security advisory for CVE-2026-44294 (CC BY 4.0)

Frequently Asked Questions

## Summary protobufjs generated JavaScript property accessors from schema-controlled field and oneof names. Certain control characters in field names were not escaped before being embedded into generated function bodies. A crafted schema or JSON descriptor could therefore cause generated encode, decode, verify, or conversion functions to fail during compilation. ## Impact An attacker who can provide or influence a protobuf schema or JSON descriptor may be able to make affected message types unusable by causing protobufjs runtime code generation to throw a syntax error. This is a denial of