How severe is CVE-2026-23737?

CVE-2026-23737 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-23737 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (40th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-23737?

CVE-2026-23737 affects Lxsmnsyc Seroval. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-23737?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-23737 have an EU (EUVD) identifier?

Yes. CVE-2026-23737 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-3679.

When was CVE-2026-23737 published?

CVE-2026-23737 was published on 2026-01-21 and last updated on 2026-06-17.

CVE-2026-23737

CVE-2026-23737 is a high-severity vulnerability in Lxsmnsyc Seroval with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-502.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (40th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-3679
Weakness: CWE-502
Affected product: Lxsmnsyc Seroval
Published: 2026-01-21
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-23737?: 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.
How severe is CVE-2026-23737?: CVE-2026-23737 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-23737 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (40th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-23737?: CVE-2026-23737 affects Lxsmnsyc Seroval. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-23737?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-23737 have an EU (EUVD) identifier?: Yes. CVE-2026-23737 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-3679.
When was CVE-2026-23737 published?: CVE-2026-23737 was published on 2026-01-21 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:lxsmnsyc:seroval:*:*:*:*:*:node.js:*:*

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