How to Fix CVE-2026-48207: Deserialization RCE in Apache Fory
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*By Sai Kiran Pandrala*
| Severity | Not verified - see advisory |
|---|---|
| Actively exploited? | Not currently listed in CISA KEV |
| Affected | 0.13.0 < 1.0.0 |
| Fixed in | See vendor advisory |
| Type (CWE) | CWE-502: Deserialization of Untrusted Data |
What is CVE-2026-48207?
CVE-2026-48207 is an unsafe deserialization in Apache Fory. The application accepts attacker-controlled serialized objects and reconstructs them without validating their type, so a crafted payload triggers code execution inside the running process. Unauthenticated remote code execution is the typical impact. Vendor description: Deserialization of untrusted data in Apache Fory PyFory. PyFory's ReduceSerializer could bypass documented DeserializationPolicy validation hooks during reduce-state restoration and global-name resolution.
Why this CVE matters
Deserialization bugs are a favorite of ransomware operators because they convert a single HTTP request into full code execution on the target host. Public proof-of-concept code for this CVE class typically appears within days of disclosure, and weaponized exploits follow shortly after.
For deployments of Apache Fory that have been exposed to the public internet during the disclosure window, the operating assumption should be that scanning has already happened. Even where exploitation has not been publicly observed, scanning for the vulnerable fingerprint is cheap and routine. Patching closes the door; log review and credential rotation close out the rest of the response.
Am I affected?
You are affected if your installation matches any of these version ranges:
- Apache Fory: 0.13.0 < 1.0.0
Check your installed version against the list above. If you cannot determine the version, treat the system as affected and follow the upgrade path below.
Run the project-specific version command (for example httpd -v, tomcat version, or check pom.xml / package metadata) and compare against the advisory.
How to fix CVE-2026-48207
- Read the vendor advisory in full: https://fory.apache.org/security/#cve-2026-48207-pyfory-reduceserializer-deserializationpolicy-bypass
- Upgrade Apache Fory to the patched build listed in the vendor advisory.
- Back up the configuration (and database, where applicable) before upgrading.
- Rotate any credentials, API keys, or session tokens that the vulnerable service touched. An unauthenticated RCE-class flaw means anything the process could see should be treated as exposed.
- Apply the patch in a maintenance window. For HA pairs, upgrade the standby node first, fail over, then upgrade the former primary.
- Restart the affected service so the patched binary loads, then verify the new version (see verification section).
Linux package upgrade
The vendor advisory (https://fory.apache.org/security/#cve-2026-48207-pyfory-reduceserializer-deserializationpolicy-bypass) names the patched build as the build named in the vendor advisory (https://fory.apache.org/security/#cve-2026-48207-pyfory-reduceserializer-deserializationpolicy-bypass).
# Ubuntu / Debian
sudo apt-get update
sudo apt-get install --only-upgrade apache2
dpkg -s apache2 | grep -i version
# RHEL / Rocky / AlmaLinux / Fedora
sudo dnf upgrade --refresh apache2 -y
rpm -q apache2
# openSUSE
sudo zypper refresh && sudo zypper update apache2
# Restart the service that loads the patched binary
sudo systemctl restart apache2 2>/dev/null || true
sudo systemctl status apache2 --no-pager 2>/dev/null || true
# Vendor advisory: https://fory.apache.org/security/#cve-2026-48207-pyfory-reduceserializer-deserializationpolicy-bypass
# Container deployments: rebuild with the patched package layer, then roll the workload.
docker pull <your-registry>/apache2:<patched-tag>
docker stop <app> && docker rm <app>
docker run -d --name <app> <your-registry>/apache2:<patched-tag>
# Kubernetes
kubectl set image deployment/<deployment-name> apache2=<your-registry>/apache2:<patched-tag>
kubectl rollout status deployment/<deployment-name>
Verify the fix landed
# Vendor advisory: https://fory.apache.org/security/#cve-2026-48207-pyfory-reduceserializer-deserializationpolicy-bypass
# 1. Compare the running version against the fixed build named above.
# (Replace the version probe with the platform-specific command from the block above.)
# 2. Re-scan with your vulnerability scanner (Nessus, Qualys, Tenable, OpenVAS).
# The scanner should no longer flag this CVE on the patched target.
# 3. Inspect recent service / kernel logs for crash loops or rollback events.
journalctl -u <service> --since "10 minutes ago"
dmesg --since "10 minutes ago"
If you cannot patch immediately
Restrict access to the management interface to trusted internal IP addresses only. Block public access at the firewall and require VPN for any remote administration. Apply the patch as soon as a maintenance window allows.
How to verify the fix worked
- After applying the patch, verify the running version in the product's admin UI or via the vendor-documented CLI command.
- Confirm the patched build matches the version listed in the vendor advisory.
- Run an authenticated vulnerability scan with a current signature set and confirm the scanner no longer flags CVE-2026-48207.
- Review logs for the entire pre-patch window for indicators of compromise listed in the vendor or CISA advisory.
- Confirm any network-layer mitigations that were applied as a stopgap have been reverted (or left in place intentionally) once the patch is verified.
If your installation was internet-reachable during the disclosure window, treat log review as part of the remediation rather than an optional follow-up. Look for unexpected administrator accounts in Apache Fory, scheduled tasks or cron jobs you did not create, new files in web-accessible directories, and outbound connections to addresses not in your baseline. Suspicious requests to the vulnerable endpoint immediately followed by successful 200-class responses with unusually large bodies are a strong indicator of exploitation.
Frequently asked questions
Is CVE-2026-48207 being exploited in the wild?
Public exploitation has not been confirmed by CISA at the time of writing. Treat the patch as time-sensitive anyway; reports often lag actual abuse.
Will a WAF or IDS rule fully mitigate CVE-2026-48207?
No. Network-layer filters can reduce noise and slow opportunistic scanners, but they will not stop a determined attacker. The vendor patch is the only durable fix.
Do I need to assume compromise if my Apache Fory was internet-facing and unpatched?
For an unauthenticated RCE-class flaw exposed to the public internet during the known exploitation window, yes. Review logs, rotate credentials the process could access, and look for unexpected accounts, scheduled tasks, or outbound connections.
References
- Official vendor advisory: https://fory.apache.org/security/#cve-2026-48207-pyfory-reduceserializer-deserializationpolicy-bypass
- NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2026-48207
- CISA KEV catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog
- Additional vendor or research reference: http://www.openwall.com/lists/oss-security/2026/05/21/10
*This guide was assembled from the official vendor advisory, the NVD record, and the CISA KEV catalog entry on 2026-05-25. Always confirm against the vendor advisory before applying changes in production.*