MediumCVE-2026-115495

    WatchGuard Mobile VPN with SSL Client: Cleartext Transmission of Sensitive Information (CVE-2026-115495)

    Published Last modified Sources: pwn.watch, BSI, CVE.org

    What is affected, what to do

    Cleartext Transmission of Sensitive Information vulnerability in the WatchGuard Mobile VPN with SSL client for Windows allows a local attacker who can capture loopback traffic to obtain the user’s VPN username and password.

    Update WatchGuard Mobile VPN with SSL Client to version 2026.4.

    Affected
    • WatchGuard Mobile VPN with SSL Client lt 12.0..2026.4
    Fixed in
    • WatchGuard Mobile VPN with SSL Client 2026.4

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

    Metrics

    5.7

    Priority

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

    Source: Vendor (CNA), CVSS v4

    5.7

    CVSS v4

    Severity Medium on the scale from 0 to 10.

    Source: pwn.watch, BSI, CVE.org

    0.1 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 0.1

    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
    58.50 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
    5.7 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
    5.7
    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
    0.1 %
    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
    0.1
    Low — this CVE sits in the lower 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
    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-319

    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

    Cleartext Transmission of Sensitive Information vulnerability in the WatchGuard Mobile VPN with SSL client for Windows allows a local attacker who can capture loopback traffic to obtain the user’s VPN username and password.

    Source: pwn.watch, BSI CSAF, BSI WID Portal, 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
    WatchGuardMobile VPN with SSL Client
    • 12.0 – < 2026.4
    • 2026.4
    WatchGuardFireware OS
    • < 12.5.22
    • < 2026.4
    • < 12.12.4
    • 12.5.22
    • 2026.4
    • 12.12.4
    WatchGuardFireware OS Mobile VPN with SSL Client
    • < 2026.4
    • 2026.4

    Vendors and products

    Weakness classes (CWE)

    • CWE-319Cleartext Transmission of Sensitive Information

      Base

      The product transmits sensitive or security-critical data in cleartext in a communication channel that can be sniffed by unauthorized actors.

      Entry at MITRE CWE-319

    References & sources

    • psirt.watchguard.comCVE-2026-115495Vendor advisory
    • pwn.watchpwn.watch: WatchGuard Fireware OS 2026.4 and 12.12.4 fix 17 Firebox flaws, including unauthenticated bugs in the SIP proxy, Access Portal and FireClusterpwn-watch
    • psirt.watchguard.comWatchGuard Security Advisories (Oct 27 2026 batch)pwn-watch
    • psirt.watchguard.comCVE-2026-93857: Fireware OS Pre-Authentication Stack Buffer Overflow in SIP Proxy Allows Remote Code Executionpwn-watch
    • psirt.watchguard.comCVE-2026-93866: Fireware OS Pre-Authentication Integer Overflow in Access Portal Allows Out-of-Bounds Writepwn-watch
    • psirt.watchguard.comCVE-2026-93865: Fireware OS Missing Authentication in FireCluster Sync Daemon Allows Remote Root Action Injectionpwn-watch
    • psirt.watchguard.comCVE-2026-112710: Fireware OS Heap Buffer Overflow in AD Authentication Service Allows Pre-Authentication Remote Code Executionpwn-watch
    • psirt.watchguard.comCVE-2026-103594: Fireware OS Stack Buffer Overflow in WireGuard Configuration Allows Remote Code Executionpwn-watch
    • psirt.watchguard.comCVE-2026-103593: Fireware OS Stack Buffer Overflow in Logging Service Allows Remote Code Executionpwn-watch

    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. ReceivedWatchGuard

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

      Weakness type: CWE-319

      Description added or changed

      Show 5 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Descriptionadded
      —
      Cleartext Transmission of Sensitive Information vulnerability in the WatchGuard Mobile VPN with SSL client for Windows allows a local attacker who can capture loopback traffic to obtain the user’s VPN username and password.
      CVSSadded
      —
      AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/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
      Weakness type (CWE)added
      —
      CWE-319
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/115xxx/CVE-2026-115495.json">CVE-2026-115495</a>
      Referenceadded
      —
      https://psirt.watchguard.com/CVE-2026-115495

      Source identifier: 5d1c2695-1a31-4499-88ae-e847036fd7e3

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