MediumCVE-2026-116583

    Seroval: Code injection through a typed array's own constructor property (CVE-2026-116583)

    Published Last modified Sources: OSV, Hersteller, CVE.org

    What is affected, what to do

    Update seroval to version 1.6.11.

    Affected
    • Lxsmnsyc Seroval gte 1.6.0, < 1.6.11..*

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    5.3

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: Vendor (CNA), CVSS v4

    5.3

    CVSS v4

    Severity Medium on the scale from 0 to 10.

    Source: OSV, Hersteller, CVE.org

    0.3 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 19.0

    Show all metrics
    Severity
    Medium
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    59.38 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    no public PoC known
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

    Read in glossary
    5.3 Methodology
    CVSS v4

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    5.3
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

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    0.3 %
    Low — model estimates < 1% exploitation likelihood.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

    Read in glossary
    19.0
    Elevated — this CVE ranks above at least 10% of all CVEs scored today.
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    —
    Published
    CISA assessment (SSVC)
    Exploitation: none known · not automatable · Technical impact: partial
    Source: CISA Vulnrichment, as of 27 October 2026
    CWE

    CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.

    Read in glossary
    CWE-79, CWE-94

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    Handle the vulnerability in regular vulnerability handling under Art. 21(2)(e) NIS2.
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    Summary

    seroval writes a typed array as a call to its constructor. In affected versions, the constructor name in the output is read from a property that data on the value can replace, and it is written without checks. A typed array that received properties from untrusted data can then put arbitrary code into the serialized output.

    Details

    Version 1.6.0 changed how seroval finds the class of an object, so that objects with their own constructor property serialize correctly. Typed arrays still took the constructor name from the value itself, so the name could come from the untrusted property instead of the array's real type.

    These functions are affected:

    • serialize, serializeAsync
    • crossSerialize, crossSerializeAsync, crossSerializeStream
    • the Serializer class
    • compileJSON

    fromJSON and fromCrossJSON are not affected: they only accept the names of the built-in typed arrays. With the compactArrayBufferViews option, the same lookup throws a TypeError instead of writing code.

    Impact

    An application is affected only when it serializes a typed array that has an own constructor property set from untrusted data. That requires code that copies properties from untrusted objects onto a typed array. This is unusual, so the severity is rated Low, even though the result is script execution in the page that receives the output.

    Patches

    Fixed in 1.6.11. The constructor name now comes from the array's internal type, which properties on the value cannot change. compactArrayBufferViews uses the real type as well.

    Workarounds

    If you cannot upgrade, do not copy properties from untrusted objects onto typed arrays, or remove an own constructor property from a typed array before serializing it.

    Source: OSV (Open Source Vulnerabilities), GitHub Security Advisories, cvelistv5, NVD (NIST)

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    lxsmnsycseroval
    • ≥ 1.6.0, < 1.6.11
    • —
    npmseroval
    • >= 1.6.0, < 1.6.11
    • 1.6.0
    • 1.6.11
    • 1.6.11

    Vendors and products

    Weakness classes (CWE)

    • CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

      Base

      The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

      Entry at MITRE CWE-79

    • CWE-94Improper Control of Generation of Code ('Code Injection')

      Base

      The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.

      Entry at MITRE CWE-94

    References & sources

    • github.comlxsmnsyc/seroval/commit/1313ebbad9687bc0245e08bfd576376e57e0e5c1x_refsource_MISC, web
    • github.comlxsmnsyc/seroval/releases/tag/seroval@1.6.11x_refsource_MISC, web
    • github.comlxsmnsyc/seroval/security/advisories/GHSA-f86p-h4j2-7qgjx_refsource_CONFIRM, web
    • NVD (NIST)vuln/detail/CVE-2026-116583advisory
    • github.comlxsmnsyc/serovalpackage

    Changes to this CVE

    Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

    1. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: none known, automatable: no

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentadded
      —
      {"id":"CVE-2026-116583","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"version":"2.0.3","timestamp":"2026-10-27T13:41:53.434470Z"}

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    2. ReceivedGitHub

      CVSS V4.0: AV:N/AC:H/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N

      Weakness type: CWE-79, CWE-94

      Description added or changed

      Show 8 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Descriptionadded
      —
      Seroval facilitates JavaScript value stringification, including complex structures beyond JSON.stringify capabilities. From 1.6.0 until 1.6.11, the JavaScript-output APIs derive a typed array's constructor name from a property on the value that can be replaced by an own constructor property. When application code copies untrusted properties onto a typed array and then passes it to serialize, serializeAsync, crossSerialize, crossSerializeAsync, crossSerializeStream, Serializer, or compileJSON, the attacker-controlled name is written as executable JavaScript and can run in the page receiving the output. This issue is fixed in version 1.6.11.
      CVSSadded
      —
      AV:N/AC:H/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
      Weakness type (CWE)added
      —
      CWE-79
      Weakness type (CWE)added
      —
      CWE-94
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/116xxx/CVE-2026-116583.json">CVE-2026-116583</a>
      Referenceadded
      —
      https://github.com/lxsmnsyc/seroval/commit/1313ebbad9687bc0245e08bfd576376e57e0e5c1
      Referenceadded
      —
      https://github.com/lxsmnsyc/seroval/releases/tag/seroval@1.6.11
      Referenceadded
      —
      https://github.com/lxsmnsyc/seroval/security/advisories/GHSA-f86p-h4j2-7qgj

      Source identifier: security-advisories@github.com

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