CVE-2026-35337
HIGHDeserialization of Untrusted Data vulnerability in Apache Storm. Versions Affected: before 2.8.6. Description: When processing topology credentials submitted via the Nimbus Thrift…
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Description
Deserialization of Untrusted Data vulnerability in Apache Storm.
Versions Affected: before 2.8.6.
Description: When processing topology credentials submitted via the Nimbus Thrift API, Storm deserializes the base64-encoded TGT blob using ObjectInputStream.readObject() without any class filtering or validation. An authenticated user with topology submission rights could supply a crafted serialized object in the "TGT" credential field, leading to remote code execution in both the Nimbus and Worker JVMs.
Mitigation: 2.x users should upgrade to 2.8.6.
Users who cannot upgrade immediately should monkey-patch an ObjectInputFilter allow-list to ClientAuthUtils.deserializeKerberosTicket() restricting deserialized classes to javax.security.auth.kerberos.KerberosTicket and its known dependencies. A guide on how to do this is available in the release notes of 2.8.6.
Credit: This issue was discovered by K.
Affected Products
stormapacheDetection & mitigation playbook
Vendor / applianceDetect
Inventory every apache storm deployment and check each version against the affected-products list above. Because the exploit targets the running system rather than your application code, also watch for remote code execution at the network and runtime layer — O3 flags the exploit behaviour from runtime telemetry and egress traffic even before a vulnerable build is confirmed.
Fix
Apply the apache storm security patch or hotfix for CVE-2026-35337 on the affected version, following the vendor advisory for your exact build.
Workarounds
Cut exposure now: restrict the management/admin interface to trusted networks, segment the device, and apply the vendor's recommended configuration mitigations and any WAF/IPS signature. O3's runtime protection blocks the exploit chain at execution, holding the line on unpatched or end-of-life systems until you can patch.
How O3 protects you
O3 detects and blocks CVE-2026-35337 exploitation at runtime: eBPF exploit-chain detection, plus L7 egress monitoring that catches the post-exploitation callback and severs the attacker's outbound channel.
Tailored to CVE-2026-35337. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-35337 being exploited in your environment?
O3's eBPF runtime sensors and L7 egress monitoring detect and block the CVE-2026-35337 exploit chain at execution — protecting unpatched and end-of-life systems until the vendor patch is applied.