CriticalCVE-2025-9242

    WatchGuard Firebox iked Out of Bounds Write Vulnerability (CVE-2025-9242)

    Published Last modified In CISA KEV since Sources: CVE.org, NCSC NZ, pwn.watch

    What is affected, what to do

    An Out-of-bounds Write vulnerability in the WatchGuard Fireware OS iked process may allow a remote unauthenticated attacker to execute arbitrary code. This vulnerability affects both the mobile user VPN with IKEv2 and the branch office VPN using IKEv2 when configured with a dynamic gateway peer.

    The vulnerability is being actively exploited; treat it as a priority. Update WatchGuard Fireware OS to version 12.11.4, WatchGuard Fireware OS to version 2025.1.1, WatchGuard Fireware OS to version 12.3.1+722811. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • WatchGuard Fireware OS lte 11.0..11.12.4+541730
    • WatchGuard Fireware OS lt 12.0..12.11.4
    • WatchGuard Fireware OS lt 2025.0..2025.1.1
    • WatchGuard Fireware OS lt 12.0..12.3.1+722811
    • WatchGuard Fireware OS lt 12.0..12.5.13
    Fixed in
    • WatchGuard Fireware OS 12.11.4
    • WatchGuard Fireware OS 2025.1.1
    • WatchGuard Fireware OS 12.3.1+722811
    • WatchGuard Fireware OS 12.5.13

    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

    9.8

    CVSS v3

    Severity Critical on the scale from 0 to 10.

    Source: CVE.org, NCSC NZ, pwn.watch

    91.8 %

    EPSS score

    High — model estimates ≥ 50% chance of real-world exploitation within 30 days.

    Source: FIRST EPSS, percentile 99.82

    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
    239.75 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
    actively exploitedSource: VulnCheck KEV (opens in a new tab) How we classify
    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
    9.8
    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
    9.3
    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“.

    Read in glossary
    91.8 %
    High — model estimates ≥ 50% chance of real-world exploitation within 30 days.
    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
    99.82
    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
    Actively exploited
    Published
    In CISA KEV since

    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
    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-787

    Response and mitigation

    Why act now?

    Prioritisation rationale

    This is a network-reachable, pre-authentication, no-user-interaction code execution flaw in a perimeter device. That puts it in the edge-appliance class attackers scan for at scale and use for initial access, and EPSS places it among the CVEs most likely to be exploited. CISA does not currently flag ransomware use, but firewall and VPN footholds are a common entry point for such campaigns. Treat any Firebox with internet-reachable IKE as critical, and patch or fence it within 24 hours. For KRITIS and NIS2 entities, confirmed exploitation should also trigger a review of incident-reporting obligations.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Inventory now: Enumerate every Firebox (hardware, FireboxV, Firebox Cloud) with its Fireware OS version and VPN configuration. Flag Mobile VPN with IKEv2, BOVPN with IKEv2 to dynamic gateway peers, and BOVPN to static peers on boxes that previously had IKEv2 configurations.
      • Apply the vendor fix: Upgrade to the fixed releases listed in the advisory: Fireware OS 2025.1.1, 12.11.4, 12.5.13, or 12.3.1+722811 (FIPS branch). Patch internet-facing units first, and roll through cluster members one at a time.
      • Handle 11.x separately: The context lists no fixed build for the 11.0 to 11.12.4+541730 branch. Treat these units as unpatchable, plan hardware replacement or migration to a supported branch, and fence them off with the mitigation layers below until then.
      • Check for compromise before patching: The bug gives an unauthenticated attacker code execution inside iked. Before upgrading, preserve the config backup, traffic logs and event logs as evidence, and diff the admin accounts and configuration against a known-good baseline.
      • Rotate secrets: If a unit was exposed and shows any indicators, rotate local admin passwords, IPSec pre-shared keys, VPN certificates and private keys, LDAP/RADIUS bind accounts, and any API or cloud credentials stored on the Firebox.

    2. Runbook step 2

      Mitigation layers

      • Configuration: Disable unused Mobile VPN with IKEv2 and dynamic-peer BOVPN configurations. Deleting them is not enough on its own: a box can remain vulnerable if a BOVPN to a static peer is still configured.
      • Network exposure: Restrict inbound IKE (UDP 500, UDP 4500) on the external interface to known peer IPs, using an alias of your BOVPN gateways, and drop everything else. Back this up with an upstream ISP or router ACL.
      • Remote-access fallback: Temporarily move mobile users to an alternative, unaffected access path, such as a separate ZTNA or VPN gateway with MFA, until the upgrade is complete.
      • IPS / network sensors: Add a rule on upstream Suricata/Snort for oversized IKE traffic to the Firebox, e.g. alert udp !$KNOWN_VPN_PEERS any -> $FIREBOX_EXT [500,4500] (msg:"Oversized IKE to Firebox - CVE-2025-9242"; dsize:>2000; sid:...;). Keep vendor signatures current.
      • Management hardening: Never expose the Web UI (TCP 8080) or management access (TCP 4117/4118) to the internet. Allow administration only from a dedicated management network, so a compromised box cannot easily pivot inward.
      • Device egress control: Limit outbound connections originating from the Firebox itself to required destinations, such as update servers, NTP, and syslog/SIEM. This hampers reverse shells and payload staging.

    3. Runbook step 3

      Detection rules

      • iked stability: Hunt Firebox event logs (via syslog into your SIEM) for crashes, hangs or restarts of the iked process. Repeated iked restarts without a matching config change strongly suggest exploitation attempts. SPL shape: index=firewall sourcetype=watchguard* "iked" ("crash" OR "restart" OR "core") | stats count by host.
      • Anomalous IKE_AUTH: Look for IKE_AUTH requests carrying unusually large CERT payloads or abnormally long certificate chains from unknown source IPs. Also flag IKE negotiations from sources that are not configured peers.
      • Network telemetry (Zeek/Suricata): Look for large UDP packets to ports 500/4500 on the Firebox from non-allowlisted sources. Zeek approach: filter conn.log on id.resp_p in {500,4500} with high orig_bytes, then join against the peer allowlist.
      • On-device post-exploitation: Treat these as signs of successful exploitation: new or modified admin accounts, unexpected policy or NAT changes, new VPN users, and the Firebox initiating connections to unknown hosts. Audit-log config commits outside change windows are also suspect.
      • Downstream signals: In EDR/NDR, treat internal sessions sourced from the Firebox IP, such as SMB, RDP or LDAP to domain controllers, as lateral-movement candidates.

    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
    Actively exploited: treat the vulnerability as a priority in vulnerability handling under Art. 21(2)(e) NIS2. If it is exploited in your environment, check the reporting obligation under Art. 23 (early warning within 24 hours).
    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
    Since 11.09.2026, manufacturers of affected products with digital elements must report actively exploited vulnerabilities under Art. 14 CRA, with an early warning within 24 hours via ENISA's single reporting platform.
    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

    An Out-of-bounds Write vulnerability in the WatchGuard Fireware OS iked process may allow a remote unauthenticated attacker to execute arbitrary code. This vulnerability affects both the mobile user VPN with IKEv2 and the branch office VPN using IKEv2 when configured with a dynamic gateway peer. If the Firebox was previously configured with the mobile user VPN with IKEv2 or a branch office VPN using IKEv2 to a dynamic gateway peer, and both of those configurations have since been deleted, that Firebox may still be vulnerable if a branch office VPN to a static gateway peer is still configured.

    Source: cvelistv5, NCSC NZ (CC BY 4.0), pwn.watch, CISA KEV Catalog, NVD (NIST), 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
    WatchGuardFireware OS
    • 12.0 – < 12.11.4
    • 12.0 – < 12.5.13
    • 2025.0 – < 2025.1.1
    • 12.0 – < 12.3.1+722811
    • 11.0 – ≤ 11.12.4+541730
    • 12.11.4
    • 12.5.13
    • 2025.1.1
    • 12.3.1+722811
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Otherwatchguardfireware2025.1
    Otherwatchguardfireware—

    Weakness classes (CWE)

    • CWE-787Out-of-bounds Write

      Base

      The product writes data past the end, or before the beginning, of the intended buffer.

      Entry at MITRE CWE-787

    Public exploit references

    Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.

    Public exploit references
    CISA KEV CatalogCISA Known Exploited Vulnerability (opens in a new tab)cisa.govactively exploited
    GitHubwatchtowrlabs/watchTowr-vs-WatchGuard-CVE-2025-9242 (opens in a new tab)github.comPoC (publicly reported)reported, not verified—
    PoC-in-GitHub (nomi-sec)WatchGuard-CVE-2025-9242-PoC-and-Mass-Scanner (opens in a new tab)github.comPoC (publicly reported)reported, not verified
    PoC-in-GitHub (nomi-sec)Mass-Scanner-CVE-2025-9242 (opens in a new tab)github.comPoC (publicly reported)reported, not verified
    PoC-in-GitHub (nomi-sec)PoC-Unauthenticated-RCE-in-WatchGuard-Fireware-12.7-Build-640389-CVE-2025-9242 (opens in a new tab)github.comPoC (publicly reported)reported, not verified

    References & sources

    • psirt.watchguard.comCVE-2025-9242Vendor advisory
    • watchguard.comWatchGuard advisory: WatchGuard FireboxVendor advisory, pwn-watch
    • github.comwatchtowrlabs/watchTowr-vs-WatchGuard-CVE-2025-9242/blob/main/w…Exploit
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2025-9242government-resource
    • pwn.watchpwn.watch: WatchGuard Firebox: Firebox Out-of-Bounds Write Vulnerabilitypwn-watch
    • NVD (NIST)NVD: CVE-2025-9242pwn-watch
    • cisa.govCISA Known Exploited Vulnerabilities Catalogpwn-watch

    Reanalysis & status changes

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

    1. Modified Analysisnvd@nist.gov

      • CPE Configuration: before AND OR *cpe:2.3:o:watchguard:fireware:2025.1:*:*:*:*:*:*:* OR cpe:2.3:h:watchguard:firebox_t115-w:*:*:*:*:*:*:*:* cpe:2.3:h:watchguard:firebox_t125:*:*:*:*:*:*:*:* cpe:2.3:h:watchguard:firebox_t125-w:*:*:*:*:*:*:*:* cpe:2.3:h:watchguard:firebox_t145:*:*:*:*:*:*:*:* cpe:2.3:h:watchguard:firebox_t145-w:*:*:*:*:*:*:*:* cpe:2.3:h:watchguard:firebox_t185:*:*:*:*:*:*:*:* after AND OR *cpe:2.3:o:watchguard:fireware:2025.1:*:*:*:*:*:*:* OR cpe:2.3:h:watchguard:firebox_t115-w:*:*:*:*:*:*:*:* cpe:2.3:h:watchguard:firebox_t125:*:*:*:*:*:*:*:* cpe:2.3:h:watchguard:firebox_t125-w:*:*:*:*:*:*:*:* cpe:2.3:h:watchguard:firebox_t145:*:*:*:*:*:*:*:* cpe:2.3:h:watchguard:firebox_t145-w:*:*:*:*:*:*:*:* cpe:2.3:h:watchguard:firebox_t185:*:*:*:*:*:*:*:* cpe:2.3:h:watchguard:firebox_m295:-:*:*:*:*:*:*:* cpe:2.3:h:watchguard:firebox_m395:-:*:*:*:*:*:*:* cpe:2.3:h:watchguard:firebox_m495:-:*:*:*:*:*:*:* cpe:2.3:h:watchguard:firebox_m595:-:*:*:*:*:*:*:* cpe:2.3:h:watchguard:firebox_m695:-:*:*:*:*:*:*:*
      • Reference Type: after WatchGuard Technologies, Inc.: https://psirt.watchguard.com/CVE-2025-9242 Types: Broken Link

    2. CVE Modified5d1c2695-1a31-4499-88ae-e847036fd7e3

      • Affected: before Fireware OS after Fireware OS, Fireware OS, Fireware OS
      • Description: before An Out-of-bounds Write vulnerability in WatchGuard Fireware OS may allow a remote unauthenticated attacker to execute arbitrary code. This vulnerability affects both the Mobile User VPN with IKEv2 and the Branch Office VPN using IKEv2 when configured with a dynamic gateway peer.This vulnerability affects Fireware OS 11.10.2 up to and including 11.12.4_Update1, 12.0 up to and including 12.11.3 and 2025.1. after An Out-of-bounds Write vulnerability in the WatchGuard Fireware OS iked process may allow a remote unauthenticated attacker to execute arbitrary code. This vulnerability affects both the mobile user VPN with IKEv2 and the branch office VPN using IKEv2 when configured with a dynamic gateway peer. If the Firebox was previously configured with the mobile user VPN with IKEv2 or a branch office VPN using IKEv2 to a dynamic gateway peer, and both of those configurations have since been deleted, that Firebox may still be vulnerable if a branch office VPN to a static gateway peer is still configured.
      • Reference: after https://psirt.watchguard.com/CVE-2025-9242
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