CVE-2019-25001
📋 TL;DR
This vulnerability in the serde_cbor Rust crate allows attackers to cause stack exhaustion through specially crafted CBOR data with deeply nested semantic tags. It affects any Rust application using serde_cbor for CBOR deserialization before version 0.10.2. Attackers can trigger denial of service by sending malicious CBOR payloads.
💻 Affected Systems
- serde_cbor Rust crate
📦 What is this software?
Serde Cbor by Serde Cbor Project
⚠️ Risk & Real-World Impact
Worst Case
Complete service unavailability due to stack exhaustion leading to crashes or resource exhaustion, potentially enabling denial of service attacks against affected services.
Likely Case
Denial of service through application crashes or degraded performance when processing malicious CBOR input, affecting service availability.
If Mitigated
Minimal impact with proper input validation, rate limiting, and updated libraries preventing exploitation.
🎯 Exploit Status
Exploitation requires sending malicious CBOR data to vulnerable deserialization endpoints. The advisory includes proof-of-concept demonstrating the issue.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.10.2
Vendor Advisory: https://rustsec.org/advisories/RUSTSEC-2019-0025.html
Restart Required: Yes
Instructions:
1. Update Cargo.toml to require serde_cbor >=0.10.2
2. Run 'cargo update serde_cbor'
3. Rebuild and redeploy your application
4. Test CBOR deserialization functionality
🔧 Temporary Workarounds
Input validation and size limits
allImplement input validation to reject CBOR data with excessive nesting depth before deserialization
Rate limiting
allImplement rate limiting on CBOR deserialization endpoints to limit impact of DoS attempts
🧯 If You Can't Patch
- Implement network-level protections like WAF rules to block suspicious CBOR payloads
- Isolate vulnerable services behind load balancers with DoS protection
🔍 How to Verify
Check if Vulnerable:
Check Cargo.lock or run 'cargo tree | grep serde_cbor' to see installed version. If version is <0.10.2, you are vulnerable.Check Version:
cargo tree | grep serde_cborVerify Fix Applied:
After updating, verify with 'cargo tree | grep serde_cbor' shows version >=0.10.2 and test CBOR deserialization with nested data.📡 Detection & Monitoring
Log Indicators:
- Application crashes with stack overflow errors
- High memory/CPU usage during CBOR processing
- Repeated failed deserialization attempts
Network Indicators:
- Unusually large or complex CBOR payloads to deserialization endpoints
- High volume of CBOR requests from single sources
SIEM Query:
source="application.log" AND ("stack overflow" OR "out of memory") AND "serde_cbor"