Unauthenticated RCE via scheduler pickle deserialization
Published Apr 23, 2026 · Updated Apr 23, 2026
Unsafe deserialization in KVCache.AI KTransformers 0 through 0.5.3 allows remote attackers to execute code through balance_serve. The scheduler's ZMQ ROUTER socket binds to all interfaces and forwards unauthenticated message bytes to worker threads that call pickle.loads(). Exploitation requires the legacy balance_serve backend and network access to its dynamic scheduler port, and code runs with the KTransformers process privileges.
Summary
What happened
Unsafe deserialization in KVCache.AI KTransformers 0 through 0.5.3 allows remote attackers to execute code through balance_serve. The scheduler's ZMQ ROUTER socket binds to all interfaces and forwards unauthenticated message bytes to worker threads that call pickle.loads(). Exploitation requires the legacy balance_serve backend and network access to its dynamic scheduler port, and code runs with the KTransformers process privileges.
The record
- CVE
- CVE-2026-26210
- Published
- Apr 23, 2026
- Updated
- Apr 23, 2026
- Vendor
- KVCache.AI
- Product
- KTransformers
- Classifications
- CWE-502, CAPEC-586, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 23, 2026CVE publishedPublication date reported by the CVE source.
- Apr 23, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <=0.5.3
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- ZMQ scheduler pickle RCE proof of conceptfunctional · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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