Authenticated code execution via unsafe JSON deserialization
Published Jan 21, 2026 · Updated Jan 21, 2026
Deserialization of untrusted data in lxsmnsyc seroval before 1.4.1 allows remote authenticated users to execute JavaScript code. The fromJSON and fromCrossJSON paths accept crafted constant-value and error records that reconstruct access to unsafe JavaScript evaluation. Exploitation requires four requests to the same function and partial knowledge of subsequent runtime use; successful code runs in the consuming application's context.
Summary
What happened
Deserialization of untrusted data in lxsmnsyc seroval before 1.4.1 allows remote authenticated users to execute JavaScript code. The fromJSON and fromCrossJSON paths accept crafted constant-value and error records that reconstruct access to unsafe JavaScript evaluation. Exploitation requires four requests to the same function and partial knowledge of subsequent runtime use; successful code runs in the consuming application's context.
The record
- CVE
- CVE-2026-23737
- Published
- Jan 21, 2026
- Updated
- Jan 21, 2026
- Vendor
- lxsmnsyc
- Product
- seroval
- Classifications
- CWE-502
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jan 21, 2026CVE publishedPublication date reported by the CVE source.
- Jan 21, 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=< 1.4.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
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
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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