Fortinet FortiOS cw_acd Flaw Added to CISA KEV
An unauthenticated heap-based buffer overflow in the cw_acd daemon of FortiOS (FortiSASE, FortiSwitchManager) allows remote code execution and is now listed on CISA's Known Exploited Vulnerabilities catalog.
Sourceadvisories.ncsc.nl — open the original
What to check
- Applies to
- The 1 CVE named below. Whether you run an affected version is not assessed: check the versions the source lists.
- Exploitation
- CISA lists CVE-2025-25249 as exploited in the wild.
NCSC-NL issued an advisory for CVE-2025-25249, a heap-based buffer overflow / out-of-bounds write vulnerability in the cw_acd daemon present in specific Fortinet FortiOS deployments, namely FortiSASE and FortiSwitchManager. The flaw can be triggered remotely by unauthenticated attackers who send specially crafted packets or requests to the vulnerable daemon, potentially resulting in arbitrary code or command execution on the affected system. This gives an attacker a path to full compromise of exposed devices without needing credentials.
On 9 September 2026, CISA added this vulnerability to its Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. NCSC-NL urges organizations to apply Fortinet's released updates immediately and to inspect internet-reachable, vulnerable systems for indicators of compromise or exploitation attempts. The CVSSv3 base score is 8.1. No specific threat actor, malware family, or IOC set was disclosed in this advisory; defenders should prioritize patching and network exposure review for FortiSASE and FortiSwitchManager instances.
Mentioned in this report
Source reporting: https://advisories.ncsc.nl/2026/ncsc-2026-0015.html
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