CVE-2026-23737 seroval Affected by Remote Code Execution via JSON Deserialization
Attackers can execute arbitrary JavaScript code by exploiting improper input handling in the seroval library's JSON deserialization functions.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-23737?
CVE-2026-23737 is a high-severity unsafe deserialization vulnerability in lxsmnsyc seroval, published on 21 Jan 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
seroval facilitates JS value stringification, including complex structures beyond JSON.stringify capabilities. In versions 1.4.0 and below, improper input handling in the JSON deserialization component can lead to arbitrary JavaScript code execution. Exploitation is possible via overriding constant value and error deserialization, allowing indirect access to unsafe JS evaluation. At minimum, attackers need the ability to perform 4 separate requests on the same function, and partial knowledge of how the serialized data is used during later runtime processing. This vulnerability affects the fromJSON and fromCrossJSON functions in a client-to-server transmission scenario. This issue has been fixed in version 1.4.0.
Weakness: CWE-502
Which versions are affected by CVE-2026-23737?
2 open source packages ship an affected version, including seroval. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
seroval npm | All versions | 1.4.1 |
seroval npm | All versions | 1.4.1 |
Products include Lxsmnsyc Seroval.
How do I fix CVE-2026-23737?
Upgrade seroval to 1.4.1 or later.
Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.
Is CVE-2026-23737 being exploited?
There is no known exploitation of CVE-2026-23737 in the wild and no public exploit code.
Other vulnerabilities in lxsmnsyc seroval
- CVE-2026-23956 seroval affected by Denial of Service via RegExp serialization
- CVE-2026-23957 seroval is vulnerable to Denial of Service via array serialization
- CVE-2026-24006 Seroval affected by Denial of Service via Deeply Nested Objects
- CVE-2026-23736 seroval Affected by Prototype Pollution via JSON Deserialization
Sources
Also known as GHSA-3rxj-6cgf-8cfw.