CVE-2026-44294: DoS in protobufjs ≤7.5.5
Platform
nodejs
Component
protobufjs
CVE-2026-44294 describes a Denial of Service (DoS) vulnerability affecting protobufjs versions 7.5.5 and earlier. An attacker can exploit this by providing a malicious protobuf schema or JSON descriptor, leading to runtime code generation errors and rendering affected message types unusable. The vulnerability was published on May 12, 2026, and mitigation strategies focus on schema validation and upgrading to a patched version.
Impact and Attack Scenarios
The primary impact of CVE-2026-44294 is a denial of service. Successful exploitation prevents the use of specific protobuf message types within applications utilizing protobufjs. This can disrupt critical functionality relying on these message formats, potentially leading to application crashes or service unavailability. The attack vector involves injecting malicious control characters into protobuf field names, which are then embedded into generated JavaScript code. This triggers syntax errors during runtime code generation, effectively disabling the message type. While the vulnerability doesn't directly expose sensitive data, the disruption of service can have significant operational consequences.
Exploitation Context
CVE-2026-44294 is currently not listed on KEV or EPSS. The CVSS score is 5.3 (Medium), indicating a moderate probability of exploitation. No public Proof-of-Concept (PoC) code has been publicly released as of the publication date. Active campaigns targeting this vulnerability are not currently known, but the ease of schema manipulation suggests potential for future exploitation.
Threat Intelligence
Exploit Status
CVSS Vector
What do these metrics mean?
- Attack Vector
- Network — remotely exploitable over the internet. No physical or local access required. Widest attack surface.
- Attack Complexity
- Low — no special conditions required. Attacker can exploit reliably without depending on rare configurations or timing.
- Privileges Required
- None — unauthenticated. No login or credentials needed to exploit.
- User Interaction
- None — attack is automatic and silent. Victim does nothing: no click, no file open.
- Scope
- Unchanged — impact is limited to the vulnerable component itself.
- Confidentiality
- None — no confidentiality impact. Attacker cannot read protected data.
- Integrity
- None — no integrity impact. Attacker cannot modify data.
- Availability
- Low — partial or intermittent denial of service. Attacker can degrade performance.
Affected Software
Weakness Classification (CWE)
Timeline
- Published
Mitigation and Workarounds
The recommended mitigation for CVE-2026-44294 is to upgrade to a patched version of protobufjs. Unfortunately, a fixed version is not yet available. As a workaround, implement strict input validation on any protobuf schemas or JSON descriptors received from untrusted sources. This validation should specifically filter out or escape control characters that could be exploited. Consider using a Web Application Firewall (WAF) to inspect and block malicious protobuf payloads. Thoroughly review and sanitize any external data used to construct protobuf messages.
How to fix
No official patch available. Check for workarounds or monitor for updates.
Frequently asked questions
What is CVE-2026-44294 — DoS in protobufjs ≤7.5.5?
CVE-2026-44294 is a Denial of Service vulnerability in protobufjs versions up to 7.5.5. A malicious protobuf schema can cause runtime code generation to fail, rendering message types unusable.
Am I affected by CVE-2026-44294 in protobufjs?
If you are using protobufjs version 7.5.5 or earlier and process protobuf schemas from untrusted sources, you are potentially affected by this vulnerability.
How do I fix CVE-2026-44294 in protobufjs?
A patched version is not yet available. Implement strict input validation on protobuf schemas and consider using a WAF to block malicious payloads.
Is CVE-2026-44294 being actively exploited?
As of the publication date, there are no known active campaigns exploiting CVE-2026-44294, but the vulnerability's nature suggests potential for future exploitation.
Where can I find the official protobufjs advisory for CVE-2026-44294?
Refer to the protobufjs project's official website and GitHub repository for updates and advisories related to CVE-2026-44294.
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