CVE-2026-22776
📋 TL;DR
A Denial of Service vulnerability exists in cpp-httplib where compressed HTTP request bodies are not properly limited after decompression. Attackers can send small compressed payloads that expand to consume excessive memory, potentially crashing affected services. This affects any application using vulnerable versions of cpp-httplib to handle HTTP requests with compression.
💻 Affected Systems
- cpp-httplib
📦 What is this software?
Cpp Httplib by Yhirose
⚠️ Risk & Real-World Impact
Worst Case
Complete service outage due to memory exhaustion, potentially affecting multiple services on the same host through resource starvation.
Likely Case
Service degradation or crashes requiring restart, leading to temporary unavailability.
If Mitigated
Minimal impact with proper memory limits and monitoring in place.
🎯 Exploit Status
Exploitation requires sending specially crafted HTTP requests with compressed bodies. The advisory includes proof-of-concept details.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.30.1
Vendor Advisory: https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-h934-98h4-j43q
Restart Required: Yes
Instructions:
1. Update cpp-httplib to version 0.30.1 or later. 2. Replace the header file in your project. 3. Recompile and redeploy affected applications. 4. Restart services using the library.
🔧 Temporary Workarounds
Disable compression support
allConfigure applications to reject HTTP requests with Content-Encoding headers
// In cpp-httplib configuration, set appropriate request handlers to reject compressed content
Implement memory limits
allAdd application-level memory monitoring and limits for request processing
🧯 If You Can't Patch
- Implement network-level filtering to block or limit compressed HTTP requests
- Deploy memory monitoring and alerting to detect abnormal memory consumption patterns
🔍 How to Verify
Check if Vulnerable:
Check if your application uses cpp-httplib version < 0.30.1 and accepts HTTP requests with Content-Encoding headers.Check Version:
grep -r "cpp-httplib" your_source_code/ && check the header file versionVerify Fix Applied:
Verify cpp-httplib version is 0.30.1 or later in your codebase and test with compressed request payloads.📡 Detection & Monitoring
Log Indicators:
- Unusual memory consumption spikes
- Service crashes/restarts
- Large decompressed payload warnings
Network Indicators:
- HTTP requests with Content-Encoding headers followed by abnormal response patterns
- Repeated compressed requests to same endpoint
SIEM Query:
source="application_logs" AND ("out of memory" OR "crash" OR "restart") AND process="your_application"