# CVE-2026-113881: Fireware OS Stack Buffer Overflow in VPN Network Access Enforcement Allows Unprivileged Code Execution

Status: published. Published: 2026-10-27. Updated: 2026-11-04.

A stack-based buffer overflow vulnerability in Fireware OS's VPN Network Access Enforcement process allows an authenticated mobile VPN user to create a denial of service condition and potentially execute arbitrary code as an unprivileged process by sending a specially crafted request.

## Remediation

- fix: Fireware OS 2026.4, Fireware OS 12.12.4 (source: CNA: WatchGuard)

## Affected products and versions

- WatchGuard / Fireware OS: ≥ 2025.1; < 2026.4 (affected, custom); ≥ 12.9; < 12.12.4 (affected, custom). Source: CNA: WatchGuard; platforms: Default

## Severity and prioritization

- CVSS 4.0: 6.1 (medium); CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N; source: CNA: WatchGuard

- CISA KEV: No listing in collected sources

- EPSS: 0.36% as of 2026-11-04; percentile 29.45%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-121, CWE-129

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://psirt.watchguard.com/CVE-2026-113881 (CNA: WatchGuard; vendor-advisory)

## Provenance

- CNA: WatchGuard: https://www.cve.org/CVERecord?id=CVE-2026-113881; retrieved 2026-11-04; source updated 2026-11-04

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-113881; retrieved 2026-11-04; source updated Not reported

Revision: df928aadd50589c904b5ba3a2272df6d924603891042fb7aee4ba207d79a0f5f

Canonical: https://y2.dev/cve/CVE-2026-113881

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