CVE-2025-59023
📋 TL;DR
This vulnerability in PowerDNS Recursor allows attackers to poison cached DNS delegations by sending crafted delegations or IP fragments. This affects PowerDNS Recursor installations that accept DNS queries from untrusted sources, potentially leading to DNS cache poisoning attacks.
💻 Affected Systems
- PowerDNS Recursor
⚠️ 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 redirect legitimate domain queries to malicious servers, enabling phishing, malware distribution, or credential theft across all users relying on the poisoned resolver.
Likely Case
Targeted DNS cache poisoning affecting specific domains, potentially redirecting users to malicious sites or intercepting sensitive communications.
If Mitigated
Limited impact with proper network segmentation and DNS query restrictions, though cache poisoning could still affect internal clients.
🎯 Exploit Status
Exploitation requires sending specially crafted DNS delegations or IP fragments to the Recursor, but no public exploit code is currently available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4.9.8, 4.10.2, or later
Vendor Advisory: https://docs.powerdns.com/recursor/security-advisories/powerdns-advisory-2025-06.html
Restart Required: Yes
Instructions:
1. Download the patched version from PowerDNS repository. 2. Stop the Recursor service. 3. Install the updated package. 4. Start the Recursor service. 5. Verify the version is 4.9.8, 4.10.2, or later.
🔧 Temporary Workarounds
Restrict Recursor Access
allLimit which clients can query the Recursor to trusted networks only
# Edit recursor.conf and set allow-from to trusted networks
allow-from=192.168.0.0/16, 10.0.0.0/8
Disable Recursion for Untrusted Sources
allConfigure Recursor to only perform recursion for authorized clients
# In recursor.conf, set:
allow-from=trusted-networks
local-address=internal-ip-only
🧯 If You Can't Patch
- Implement strict network ACLs to only allow DNS queries from trusted internal networks
- Monitor DNS logs for unusual delegation patterns or cache poisoning attempts
🔍 How to Verify
Check if Vulnerable:
Check PowerDNS Recursor version with 'rec_control version' or 'pdns_recursor --version'Check Version:
rec_control versionVerify Fix Applied:
Verify version is 4.9.8, 4.10.2, or later using version check command📡 Detection & Monitoring
Log Indicators:
- Unusual delegation patterns in Recursor logs
- Multiple failed delegation attempts from single sources
- Cache statistics showing abnormal delegation cache growth
Network Indicators:
- DNS queries with crafted delegation records
- Unusual IP fragmentation in DNS traffic
- Multiple identical delegation queries from suspicious sources
SIEM Query:
source="powerdns-recursor" ("delegation" OR "cache") AND ("error" OR "unusual" OR "malformed")