CriticalCVE-2026-129124

    C-Kermit before 11.1.515 OS Command Injection via REMOTE WHO and REMOTE SPACE (CVE-2026-129124)

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

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    What is affected, what to do

    C-Kermit before 11.1.515 contains an OS command injection vulnerability that allows remote clients to execute shell commands by supplying unquoted arguments to REMOTE WHO or REMOTE SPACE. Attackers can append shell metacharacters to arguments passed through WHOCMD or SPACM2 to syscmd(), executing commands on the server host even when DISABLE HOST is set.

    Update OpenKermit C-Kermit to version 11.1.515.

    Affected
    • OpenKermit C-Kermit lt *..11.1.515
    Fixed in
    • OpenKermit C-Kermit 11.1.515

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

    Metrics

    9.2

    XIEM Effective CVSS

    Highest available CVSS rating from NVD and vendor data.

    Source: Vendor (CNA), CVSS v4

    8.1

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: OSV, CVE.org, EUVD

    —

    EPSS score

    No value is available for this vulnerability.

    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
    76.00 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
    9.2 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
    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
    9.2
    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-78

    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

    C-Kermit before 11.1.515 contains an OS command injection vulnerability that allows remote clients to execute shell commands by supplying unquoted arguments to REMOTE WHO or REMOTE SPACE. Attackers can append shell metacharacters to arguments passed through WHOCMD or SPACM2 to syscmd(), executing commands on the server host even when DISABLE HOST is set.

    Source: OSV (Open Source Vulnerabilities), NVD (NIST), ENISA EUVD, cvelistv5, CVE.org (MITRE)

    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
    OpenKermitC-Kermit
    • < 11.1.515
    • 11.1.515

    Vendors and products

    Weakness classes (CWE)

    • CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

      Base

      The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.

      Entry at MITRE CWE-78

    References & sources

    • github.comGitHub Security Advisory (GHSA-c5px-7h4c-gj8p)euvd, Vendor advisory, advisory
    • github.comOpenKermit/ckermit/commit/29c4bfbe12d685f93668350c24291e562029f…euvd, Patch
    • github.comC-Kermit v11.1.515 Release Noteseuvd, Release notes, advisory
    • github.comOpenKermit/ckermit/blob/v11.0.514/ckcpro.weuvd, Technical description
    • vulncheck.comVulnCheck Advisory: C-Kermit before 11.1.515 OS Command Injection via REMOTE WHO and REMOTE SPACEeuvd, Third-party advisory
    • NVD (NIST)vuln/detail/CVE-2026-129124euvd
    • github.comCVEProject/cvelistV5/tree/main/cves/2026/129xxx/CVE-2026-129122…advisory
    • github.comOpenKermit/ckermit/blob/v11.0.514/ckctel.carticle
    • github.comOpenKermit/ckermit/commit/39ab009a365b97632e9975e1266fa618c4bdc…fix
    • github.comOpenKermit/ckermit/commit/42cf6decb926f56d606a76262791aaf071955…fix
    • NVD (NIST)vuln/detail/CVE-2026-129122advisory
    • vulncheck.comadvisories/c-kermit-6.0.192-before-11.1.515-buffer-overflow-via…advisory
    • github.comCVEProject/cvelistV5/tree/main/cves/2026/129xxx/CVE-2026-129123…advisory
    • github.comOpenKermit/ckermit/blob/v11.0.514/ckcftp.carticle
    • github.comOpenKermit/ckermit/commit/bec28a4d544031fa07a07aacba3df5dd1202e…fix
    • NVD (NIST)vuln/detail/CVE-2026-129123advisory
    • vulncheck.comadvisories/c-kermit-8.0.200-before-11.1.515-ftp-client-buffer-o…advisory
    • github.comCVEProject/cvelistV5/tree/main/cves/2026/129xxx/CVE-2026-129125…advisory
    • github.comOpenKermit/ckermit/blob/v11.0.514/ckcpro.warticle
    • github.comOpenKermit/ckermit/commit/85ef1da670cee132ea2d8e4eb759bab310ff7…fix

    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. ReceivedVulnCheck

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

      CVSS V3.1: AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

      Weakness type: CWE-78

      Description added or changed

      Show 10 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Descriptionadded
      —
      C-Kermit before 11.1.515 contains an OS command injection vulnerability that allows remote clients to execute shell commands by supplying unquoted arguments to REMOTE WHO or REMOTE SPACE. Attackers can append shell metacharacters to arguments passed through WHOCMD or SPACM2 to syscmd(), executing commands on the server host even when DISABLE HOST is set.
      CVSSadded
      —
      AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/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
      CVSSadded
      —
      AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
      Weakness type (CWE)added
      —
      CWE-78
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/129xxx/CVE-2026-129124.json">CVE-2026-129124</a>
      Referenceadded
      —
      https://github.com/OpenKermit/ckermit/blob/v11.0.514/ckcpro.w#L1423
      Referenceadded
      —
      https://github.com/OpenKermit/ckermit/commit/29c4bfbe12d685f93668350c24291e562029ff57
      Referenceadded
      —
      https://github.com/OpenKermit/ckermit/releases/tag/v11.1.515
      Referenceadded
      —
      https://github.com/OpenKermit/ckermit/security/advisories/GHSA-c5px-7h4c-gj8p
      Referenceadded
      —
      https://www.vulncheck.com/advisories/c-kermit-before-11.1.515-os-command-injection-via-remote-who-and-remote-space

      Source identifier: disclosure@vulncheck.com

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