CVE-2025-22868: Go Jws DOS Vulnerability

CVE-2025-22868 Overview

CVE-2025-22868 is a memory exhaustion vulnerability affecting the Go JWS (JSON Web Signature) package. An attacker can pass a malicious malformed token which causes unexpected memory to be consumed during parsing. This vulnerability allows remote attackers to trigger denial of service conditions by exploiting improper validation of token structures within the JWS parsing mechanism.

Critical Impact

Remote attackers can cause denial of service through memory exhaustion by sending specially crafted malformed JWS tokens to applications using the vulnerable Go JWS package.

Affected Products

• Go JWS package (all versions prior to the security patch)

Discovery Timeline

• 2025-02-26 - CVE CVE-2025-22868 published to NVD
• 2025-05-01 - Last updated in NVD database

Technical Details for CVE-2025-22868

Vulnerability Analysis

This vulnerability stems from improper input validation when parsing JWS (JSON Web Signature) tokens. The Go JWS package fails to adequately validate token structure before allocating memory for parsing operations. When processing a maliciously crafted token, the parser can be tricked into consuming excessive memory, leading to resource exhaustion.

The vulnerability is classified under CWE-1286 (Improper Validation of Syntactic Correctness of Input), indicating that the parser does not properly verify the syntactic structure of incoming tokens before proceeding with memory-intensive operations. This allows attackers to craft tokens that exploit the parsing logic to allocate disproportionate amounts of memory relative to the input size.

Root Cause

The root cause lies in the JWS token parsing logic which does not properly validate or limit memory allocation when processing malformed tokens. The parser may allocate memory based on attacker-controlled values within the token structure without implementing appropriate bounds checking. This improper validation of syntactic correctness allows malformed input to trigger unbounded memory consumption.

Attack Vector

The attack can be executed remotely over the network without any authentication or user interaction required. An attacker needs to send a specially crafted malformed JWS token to an application that uses the vulnerable Go JWS package for token parsing. When the application attempts to parse the malicious token, it will consume excessive memory, potentially leading to:

1. Application crashes due to out-of-memory conditions
2. Service degradation as system resources become exhausted
3. Complete denial of service for the affected application

The attack does not require any privileges and can be executed against any network-exposed endpoint that processes JWS tokens using the vulnerable package.

Detection Methods for CVE-2025-22868

Indicators of Compromise

• Unusual memory consumption spikes in applications processing JWS tokens
• Sudden increases in memory allocation patterns during token parsing operations
• Application crashes or restarts due to out-of-memory errors
• Abnormally large or malformed JWS token submissions in application logs

Detection Strategies

• Monitor application memory usage for sudden, unexplained increases during token processing
• Implement logging for JWS token parsing operations to identify malformed input patterns
• Set up alerts for memory threshold breaches in services that handle JWT/JWS authentication
• Deploy application performance monitoring (APM) to track resource consumption anomalies

Monitoring Recommendations

• Configure memory usage alerts for applications utilizing the Go JWS package
• Implement rate limiting on endpoints that accept JWS tokens to mitigate bulk exploitation attempts
• Enable detailed logging for authentication and token validation services
• Monitor for patterns of failed token parsing attempts that may indicate probing activity

How to Mitigate CVE-2025-22868

Immediate Actions Required

• Update the Go JWS package to the patched version immediately
• Review all applications using the Go JWS package and prioritize updates for internet-facing services
• Implement memory limits at the application or container level to contain potential exploitation
• Consider temporarily disabling endpoints that process JWS tokens if patching is not immediately possible

Patch Information

The Go development team has addressed this vulnerability. Refer to the Go Developer Community Post for the specific code changes and the Go Issue Tracker Entry for additional context. The Go Vulnerability Advisory GO-2025-3488 provides comprehensive information about affected versions and remediation guidance.

Workarounds

• Implement input size limits on JWS tokens before they reach the parsing library
• Deploy a Web Application Firewall (WAF) with rules to filter abnormally large or malformed tokens
• Configure memory limits using containerization technologies (Docker, Kubernetes) to prevent complete system exhaustion
• Implement circuit breakers that temporarily disable token processing when memory thresholds are exceeded