CriticalCVE-2026-4800

    Apache Kafka: Improper Control of Generation of Code ('Code Injection') (CVE-2026-4800)

    Published Last modified

    What is affected, what to do

    A flaw was found in lodash. The fix for CVE-2021-23337 added validation for the variable option in _.template but did not apply the same validation to options.imports key names.

    Update Lodash to version 4.18.1, Lodash-es to version 4.18.1, Lodash-amd to version 4.18.1.

    Affected
    • Lodash lt 4.0.0..4.18.1
    • Lodash-es lt 4.0.0..4.18.1
    • Lodash-amd lt 4.0.0..4.18.1
    • Lodash.template lt 4.0.0..4.18.1
    Fixed in
    • Lodash 4.18.1
    • Lodash-es 4.18.1
    • Lodash-amd 4.18.1
    • Lodash.template 4.18.1

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

    Metrics

    9.8

    Priority

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

    Source: NVD, CVSS v3

    8.1

    CVSS v3

    Severity High on the scale from 0 to 10.

    2.6 %

    EPSS score

    Moderate — model estimates 1-10% exploitation likelihood.

    Source: FIRST EPSS, percentile 85.2

    Show all metrics
    Severity
    Critical
    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
    87.22 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
    9.8 Methodology
    CVSS v3

    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
    8.1
    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“.

    Read in glossary
    2.6 %
    Moderate — model estimates 1-10% 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
    85.2
    Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
    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
    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-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
    High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
    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

    A flaw was found in lodash. The fix for CVE-2021-23337 added validation for the variable option in _.template but did not apply the same validation to options.imports key names. Both paths flow into the same Function() constructor sink. Additionally, _.template uses assignInWith to merge imports, which enumerates inherited properties via for..in. If Object.prototype has been polluted by any other vector, the polluted keys are copied into the imports object and passed to Function().

    Source: BSI WID Portal

    Affected products

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

    Affected products
    VendorProductAffected versionsFixed in
    Apache Software FoundationApache Kafka
    • 4.1.0 – ≤ 4.1.1
    • —
    Apache Software FoundationApache Log4j JSON Template Layout
    • 2.14.0 – < 2.25.4
    • 3.0.0-alpha1 – ≤ 3.0.0-beta3
    • 2.25.4
    • —
    Apache Software FoundationApache Neethi
    • < 3.2.2
    • 3.2.2
    Apache Software FoundationApache ZooKeeper
    • 3.8.0 – ≤ 3.8.5
    • 3.9.0 – ≤ 3.9.4
    • —
    • —
    FasterXMLjackson-databind
    • ≥ 2.8.0, < 2.18.9
    • —
    lodashlodash
    • 4.0.0 – < 4.18.1
    • 4.0.0 – < 4.18.0
    • 4.18.1
    • 4.18.0
    lodashlodash-amd
    • 4.0.0 – < 4.18.1
    • 4.0.0 – < 4.18.0
    • 4.18.1
    • 4.18.0
    lodashlodash-es
    • 4.0.0 – < 4.18.1
    • 4.0.0 – < 4.18.0
    • 4.18.1
    • 4.18.0
    lodashlodash.template
    • 4.0.0 – < 4.18.1
    • 4.0.0 – < 4.18.0
    • 4.18.1
    • 4.18.0
    apachekafka
    • 4.1.0 – < 4.1.2
    • 4.1.2
    apachelog4j
    • 2.14.0 – < 2.25.4
    • 3.0.0
    • 2.25.4
    • —
    apacheneethi
    • < 3.2.2
    • 3.2.2
    apachezookeeper
    • 3.8.0 – < 3.8.6
    • 3.9.0 – < 3.9.5
    • 3.8.6
    • 3.9.5
    fasterxmljackson-databind
    • 2.19.0 – < 2.21.5
    • 2.22.0
    • 2.8.0 – < 2.18.9
    • 3.0.0 – < 3.1.4
    • 2.21.5
    • —
    • 2.18.9
    • 3.1.4
    ApacheKafka
    • < 3.9.2
    • < 4.0.1
    • < 4.1.2
    • < 4.2.0
    • 3.9.2
    • 4.0.1
    • 4.1.2
    • 4.2.0
    FasterXMLJackson
    • < 2.14.0
    • < 2.18.8
    • < 2.18.9
    • < 2.21.4
    • < 2.21.5
    • < 3.1.4
    • 2.14.0
    • 2.18.8
    • 2.18.9
    • 2.21.4
    • 2.21.5
    • 3.1.4
    IBMApp Connect Enterprise Certified Container
    • < 12.0.12.26
    • < 12.0.24
    • < 13.0.7.2
    • < 13.1.0
    • 12.0.12.26
    • 12.0.24
    • 13.0.7.2
    • 13.1.0
    IBMConcert
    • < 3.0.0
    • 3.0.0
    IBMOperational Decision Manager
    • <8.11.0.1 IF056
    • <8.11.1 IF055
    • <8.12.0.1 IF039
    • <9.0.0.1 IF025
    • <9.5.0.1 IF010
    • —
    • —
    • —
    • —
    • —
    IBMQRadar SIEM
    • <7.5.0 UP15 IF06
    • <7.5.0 UP16 IF01
    • < 7.6.0.3
    • —
    • —
    • 7.6.0.3
    From bundled advisories, not CVE-specific (65)

    Product list of a bundled advisory that does not state which product this CVE affects.

    Products from bundled advisories
    VendorProductAffected versionsFixed in
    Apachelog4j
    • < 2.25.4
    • 2.25.4
    AtlassianBamboo Data Center LTS
    • < 10.2.22
    • < 10.2.23
    • < 12.1.10
    • < 12.1.11
    • 10.2.22
    • 10.2.23
    • 12.1.10
    • 12.1.11
    AtlassianBamboo LTS
    • < 10.2.21
    • < 12.1.9
    • 10.2.21
    • 12.1.9
    AtlassianBitbucket Data Center
    • < 10.4.2
    • < 10.4.3
    • 10.4.2
    • 10.4.3
    AtlassianBitbucket Data Center LTS
    • < 10.2.6
    • < 10.2.7
    • < 9.4.23
    • < 9.4.24
    • 10.2.6
    • 10.2.7
    • 9.4.23
    • 9.4.24
    AtlassianBitbucket LTS
    • < 10.3.2
    • < 9.4.22
    • 10.3.2
    • 9.4.22
    AtlassianConfluence Data Center LTS
    • < 10.2.15
    • < 10.2.17
    • < 10.2.18
    • < 9.2.23
    • < 9.2.24
    • < 9.2.25
    • 10.2.15
    • 10.2.17
    • 10.2.18
    • 9.2.23
    • 9.2.24
    • 9.2.25
    AtlassianConfluence LTS
    • < 10.2.14
    • < 9.2.22
    • 10.2.14
    • 9.2.22
    AtlassianCrucible
    • < 4.9.12
    • < 4.9.13
    • < 4.9.14
    • 4.9.12
    • 4.9.13
    • 4.9.14
    AtlassianFisheye
    • < 4.9.12
    • < 4.9.13
    • < 4.9.14
    • 4.9.12
    • 4.9.13
    • 4.9.14
    AtlassianJira Data Center LTS
    • < 10.3.24
    • < 10.3.25
    • < 11.3.10
    • < 11.3.11
    • 10.3.24
    • 10.3.25
    • 11.3.10
    • 11.3.11
    AtlassianJira LTS
    • < 10.3.23
    • < 11.3.8
    • 10.3.23
    • 11.3.8
    AtlassianJira Service Management Data Center LTS
    • < 10.3.25
    • < 11.3.11
    • 10.3.25
    • 11.3.11
    HCLBigFix
    • WebUI
    • —
    IBMSPSS
    • Modeler
    • —
    IBMTivoli Netcool/OMNIbus
    • 8.1.0-8.1.0.36
    • —
    IBMWebSphere Application Server
    • <8.5.5.29 PH71714
    • <8.5.5.29 PH71757
    • <8.5.5.30 PH71706
    • < 8.5.5.31
    • <9.0.5.28 PH71706
    • <9.0.5.28 PH71714
    • <9.0.5.28 PH71757
    • < 9.0.5.29
    • —
    • —
    • —
    • 8.5.5.31
    • —
    • —
    • —
    • 9.0.5.29

    Weakness classes (CWE)

    • 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

    Reanalysis & status changes

    Chronological NVD audit events for this CVE — reanalyses, CVSS updates, CPE diffs.

    1. CVE Modifiedce714d77-add3-4f53-aff5-83d477b104bb

      • Description: before Impact: The fix for CVE-2021-23337 (https://github.com/advisories/GHSA-35jh-r3h4-6jhm) added validation for the variable option in _.template but did not apply the same validation to options.imports key names. Both paths flow into the same Function() constructor sink. When an application passes untrusted input as options.imports key names, an attacker can inject default-parameter expressions that execute arbitrary code at template compilation time. Additionally, _.template uses assignInWith to merge imports, which enumerates inherited properties via for..in. If Object.prototype has been polluted by any other vector, the polluted keys are copied into the imports object and passed to Function(). Patches: Users should upgrade to version 4.18.0. Workarounds: Do not pass untrusted input as key names in options.imports. Only use developer-controlled, static key names. after The fix for CVE-2021-23337 added validation for the variable option in _.template but did not apply the same validation to options.imports key names, and both paths flow into the same Function() constructor sink. When an application passes untrusted input as options.imports key names, an attacker can inject default-parameter expressions that execute arbitrary code at template compilation time. Additionally, _.template uses assignInWith to merge imports, which enumerates inherited properties via for..in, so if Object.prototype has been polluted by another vector the polluted keys are copied into the imports object and passed to Function(). The issue is fixed in 4.18.1 for lodash, lodash-es, lodash-amd, and lodash.template. As a workaround, do not pass untrusted input as key names in options.imports; use only developer-controlled, static key names.
      • Affected: after Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/4xxx/CVE-2026-4800.json">CVE-2026-4800</a>
      • Reference: after https://github.com/lodash/lodash/security/advisories/GHSA-r5fr-rjxr-66jc
      • Reference: before https://github.com/advisories/GHSA-35jh-r3h4-6jhm

    2. CVE Modified0b0ca135-0b70-47e7-9f44-1890c2a1c46c

      • Affected: after Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/4xxx/CVE-2026-4800.json">CVE-2026-4800</a>

    3. CVE Modified0b0ca135-0b70-47e7-9f44-1890c2a1c46c

      • Affected: after Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/4xxx/CVE-2026-4800.json">CVE-2026-4800</a>

    4. CVE Modified0b0ca135-0b70-47e7-9f44-1890c2a1c46c

      • Affected: after Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/4xxx/CVE-2026-4800.json">CVE-2026-4800</a>

    5. CVE Modified0b0ca135-0b70-47e7-9f44-1890c2a1c46c

      • Affected: after Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/4xxx/CVE-2026-4800.json">CVE-2026-4800</a>
      • Reference: after https://access.redhat.com/errata/RHSA-2026:59833

    Linked CVEs

    Linked CVEs
    SeverityCVETitleCVSSExploitation
    MediumCVE-2026-54515jackson-databind: Case-insensitive deserialization bypasses per-property @JsonIgnoreProperties5.3—
    CriticalCVE-2026-4800lodash vulnerable to Code Injection via `_.template` imports key names9.8—
    HighCVE-2026-42402Apache Neethi: Policy Normalization Unbounded Resource Allocation DoS7.5—
    HighCVE-2026-34481Apache Log4j JSON Template Layout: Improper Encoding or Escaping of Output7.5—
    CriticalCVE-2026-33557Apache Kafka: Missing JWT token validation in OAUTHBEARER authentication9.1—
    HighCVE-2026-24308Apache ZooKeeper: Sensitive information disclosure in client configuration handling7.5—
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    Badge preview for CVE-2026-4800
    <a href="https://intel.neosec.eu/en/cve/CVE-2026-4800"><img src="https://intel.neosec.eu/badge/cve/CVE-2026-4800.svg?lang=en" alt="CVE-2026-4800 – NEOSEC Intel" height="20"></a>