How severe is CVE-2025-9242?

CVE-2025-9242 has a CVSS score of 9.8/10, rated CRITICAL. Immediate patching is strongly recommended.

Which products are affected by CVE-2025-9242?

Affected package information for CVE-2025-9242 is not yet fully mapped. Check the official advisory links for details.

How do I patch CVE-2025-9242?

Apply the watchguard fireware security patch or hotfix for CVE-2025-9242 on the affected version, following the vendor advisory for your exact build.

How do I detect CVE-2025-9242 across my infrastructure?

Inventory every watchguard fireware deployment and check each version against the affected-products list above. Because the exploit targets the running system rather than your application code, also watch for remote code execution at the network and runtime layer — O3 flags the exploit behaviour from runtime telemetry and egress traffic even before a vulnerable build is confirmed.

How do I mitigate CVE-2025-9242 if there is no patch (or I can't update yet)?

Cut exposure now: restrict the management/admin interface to trusted networks, segment the device, and apply the vendor's recommended configuration mitigations and any WAF/IPS signature. O3's runtime protection blocks the exploit chain at execution, holding the line on unpatched or end-of-life systems until you can patch.

How does O3 Security protect against CVE-2025-9242?

O3 detects and blocks CVE-2025-9242 exploitation at runtime: eBPF exploit-chain detection, plus L7 egress monitoring that catches the post-exploitation callback and severs the attacker's outbound channel.

Is CVE-2025-9242 actively exploited in the wild?

Yes. There are 2 known exploit references for CVE-2025-9242, including . All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2025-9242?

CVE-2025-9242 has an EPSS (Exploit Prediction Scoring System) score of 91.1%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

Is CVE-2025-9242 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2025-9242 (WatchGuard Firebox Out-of-Bounds Write Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2025-11-12. CISA required all US federal civilian agencies to remediate this vulnerability by 2025-12-03. The required action was: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2025-9242?

CVE-2025-9242 is classified as Out-of-bounds Write (CWE-787). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Which products and versions are affected by CVE-2025-9242?

CVE-2025-9242 affects watchguard fireware (1 version, e.g. 2025.1). Check the affected-products list on this page against your deployed version to confirm exposure.

When was CVE-2025-9242 published, and has it been updated?

CVE-2025-9242 was published on September 17, 2025 and was last updated on June 17, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CISA KEV·Added 2025-11-12 — agencies required to remediate by 2025-12-03

CVE-2025-9242

CRITICAL

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…

Published

Sep 17, 2025

Updated

Jun 17, 2026

Affected

0 pkgs

Patched

None yet

Exploits

2 known

EPSS Exploitation Probability

via FIRST.org ↗

91.1%probability of exploitation in next 30 days

Very High Risk100th percentile+4.75%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Description

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.

Affected Products

1 product · 3 configurations

firewarewatchguard

≥ 11.10.2 && < 12.5.13

1 version

2025.1

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

watchtowrlabs/watchTowr-vs-WatchGuard-CVE-2025-9242

⭐ 13🍴 5Mar 2026

UnusualGiraffe/Mass-Scanner-CVE-2025-9242

Detection-only asynchronous IPv4 scanner for identifying WatchGuard Fire

⭐ 3🍴 0Jul 2026

Detection & mitigation playbook

Vendor / appliance

Detect
Inventory every watchguard fireware deployment and check each version against the affected-products list above. Because the exploit targets the running system rather than your application code, also watch for remote code execution at the network and runtime layer — O3 flags the exploit behaviour from runtime telemetry and egress traffic even before a vulnerable build is confirmed.
Fix
Apply the watchguard fireware security patch or hotfix for CVE-2025-9242 on the affected version, following the vendor advisory for your exact build.
Workarounds
Cut exposure now: restrict the management/admin interface to trusted networks, segment the device, and apply the vendor's recommended configuration mitigations and any WAF/IPS signature. O3's runtime protection blocks the exploit chain at execution, holding the line on unpatched or end-of-life systems until you can patch.
How O3 protects you
O3 detects and blocks CVE-2025-9242 exploitation at runtime: eBPF exploit-chain detection, plus L7 egress monitoring that catches the post-exploitation callback and severs the attacker's outbound channel.

Tailored to CVE-2025-9242. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

O3 Security · Runtime Protection

Is CVE-2025-9242 being exploited in your environment?

O3's eBPF runtime sensors and L7 egress monitoring detect and block the CVE-2025-9242 exploit chain at execution — protecting unpatched and end-of-life systems until the vendor patch is applied.

Protect my workloads How runtime protection works