CVE-2025-4035
📋 TL;DR
A vulnerability in libsoup allows malicious websites to bypass public suffix protections and set cookies for domains they don't own when the domain contains at least two components and includes an uppercase character. This could lead to session fixation attacks where attackers hijack user sessions. Affected systems include those using vulnerable versions of libsoup for HTTP client operations.
💻 Affected Systems
- libsoup
- applications using libsoup for HTTP client functionality
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Attackers could hijack user sessions on legitimate websites by setting malicious cookies, potentially leading to account takeover, data theft, or unauthorized actions performed as the victim.
Likely Case
Targeted session fixation attacks against users visiting malicious websites, potentially compromising accounts on sites that rely on cookie-based authentication.
If Mitigated
Limited impact if websites implement additional session security measures like secure flags, HTTP-only cookies, and proper session management.
🎯 Exploit Status
Exploitation requires user interaction (visiting malicious website) but the technical complexity is low once the malicious site is created.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check vendor advisories for specific fixed versions
Vendor Advisory: https://access.redhat.com/errata/RHSA-2025:8128
Restart Required: Yes
Instructions:
1. Check your distribution's security advisories. 2. Update libsoup package using your package manager. 3. Restart affected applications or services using libsoup. 4. For Red Hat systems: 'yum update libsoup' and reboot if required.
🔧 Temporary Workarounds
Disable cookie processing in applications
linuxConfigure applications to disable cookie handling or use alternative HTTP libraries
Application-specific configuration required
Use browser-based HTTP clients instead
allFor applications that can use browser engines instead of libsoup directly
Application architecture change required
🧯 If You Can't Patch
- Implement web application firewalls (WAF) to detect and block malicious cookie setting attempts
- Monitor for unusual cookie patterns in application logs and implement alerting for suspicious domain cookie attempts
🔍 How to Verify
Check if Vulnerable:
Check libsoup version: 'rpm -q libsoup' (RHEL/Fedora) or 'dpkg -l | grep libsoup' (Debian/Ubuntu) and compare against patched versions in vendor advisories.Check Version:
rpm -q libsoup --queryformat '%{VERSION}-%{RELEASE}\n'Verify Fix Applied:
Verify updated version is installed and test cookie handling with known test cases from security advisories.📡 Detection & Monitoring
Log Indicators:
- Unusual cookie domain patterns in application logs
- Multiple cookie set attempts from single sources
Network Indicators:
- HTTP requests setting cookies for domains with uppercase characters in multi-component domains
SIEM Query:
http.cookie contains *[A-Z]* AND http.host contains '.' AND count(http.host, '.') >= 1