CVE-2022-38493

What it actually does

The library performs RSA-OAEP decryption on a crafted JWE token without first validating the RSA private key length, triggering a crash or resource exhaustion that results in denial of service.

Why it matters to the business

Services that rely on this library for processing encrypted tokens can be disrupted or taken offline by a single malicious request, causing availability loss and potential operational downtime.

How an attack unfolds

An attacker creates a malformed JWE token containing an RSA-OAEP payload with an invalid private key length, then submits it to any endpoint that invokes the vulnerable decryption routine, causing the process to fail without authentication or special privileges.

How to fix it

Upgrade Rhonabwy to version 1.1.7 or later; apply the corresponding fixed package versions for any downstream distributions listed in the affected products.

How to confirm the fix worked

Confirm the installed library version meets or exceeds 1.1.7, then test decryption of both valid and malformed JWE tokens to verify the key-length check prevents crashes.

Typical attack path

1. Locate an application endpoint that accepts and decrypts JWE tokens
2. Generate a crafted JWE payload with an invalid RSA key length for OAEP
3. Transmit the token over the network to trigger the decryption path
4. Induce a crash or hang resulting in denial of service

How to detect it

Review application and system logs for unexpected crashes or high resource usage during JWE decryption operations; correlate with incoming requests containing JWE structures around the time of the incident.

What your security team should do

• Prioritize upgrade of the affected library across all instances before the CISA remediation window if applicable
• Add rate limiting and request validation around JWE processing endpoints
• Monitor application logs and process health for sudden terminations during token handling