Security Digest · Vulnerability record · Known exploited
CVE-2025-9242: WatchGuard Firebox Out-of-Bounds Write Vulnerability
Exploited in the wild (CISA KEV). An Out-of-bounds Write vulnerability in the WatchGuard Fireware OS iked process may allow a remote unauthenticated attacker to execute arbitrary code.
CISA KEV · added 2025-11-12 CVSS 9.3 Critical EPSS 91.8% · p99.8
Should you act?
Exploited: patch now if you run it
CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- Yes, if you run WatchGuard Firebox. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2025-11-12, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2025-12-03; treat that as the outer limit, not the target.
- EPSS 91.8%, percentile 99.8: FIRST’s model estimates a 91.8% chance of exploitation activity in the next 30 days, higher than 99.8% of all scored CVEs (very high). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
What it is
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.
CISA’s summary
WatchGuard Firebox contains an out-of-bounds write vulnerability in the OS iked process that may allow a remote unauthenticated attacker to execute arbitrary code.
Weakness type: CWE-787.
Product: WatchGuard Firebox · Assigned by: WatchGuard · Published: 2025-09-17
Affected and fixed versions
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| WatchGuard | Fireware OS | 11.0 <= 11.12.4+541730, 12.0 < 12.11.4, 2025.0 < 2025.1.1 |
| WatchGuard | Fireware OS | 12.0 < 12.3.1+722811 |
| WatchGuard | Fireware OS | 12.0 < 12.5.13 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| WatchGuard | 4.0 | 9.3 Critical | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Attack requirements: none
- Privileges required: none (no login)
- User interaction: none
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: added 2025-11-12; federal due date 2025-12-03. Known ransomware use: Unknown.
- CISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- CISA SSVC assessment: exploitation active, automatable yes, technical impact total.
- FIRST EPSS (model of 2026-10-21): 91.80% probability of exploitation activity in the next 30 days; percentile 99.8.
Timeline
- — CVE record published by WatchGuard
- — Added to CISA’s Known Exploited Vulnerabilities catalog
- — CISA remediation deadline for US federal agencies
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vendor and project advisories, patches
- psirt.watchguard.com psirt.watchguard.com
- watchguard.com watchguard.com
Vulnerability records
- CVE.org record CVE-2025-9242 cve.org
- NVD entry CVE-2025-9242 nvd.nist.gov
Government
Other references from the CVE record and advisory
- github.com github.com
All exploited WatchGuard vulnerabilities · Today’s Security Digest