EUVD-2026-26256Severity by source
AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Admin credentials required (PR:H); management interface network-reachable (AV:N); crash yields total firewall availability loss (A:H) with no confidentiality or integrity impact.
Primary rating from NVD.
CVSS VectorNVD
Lifecycle Timeline
4DescriptionCVE.org
A post-authentication Stack-based Buffer Overflow vulnerabilities in SonicOS allows a remote attacker to crash a firewall.
AnalysisAI
Stack-based buffer overflow in SonicWall SonicOS enables authenticated remote attackers with high-privilege credentials to crash the firewall, producing a complete denial-of-service condition across multiple SonicOS release trains. Affected deployments span SonicOS 6.5.x, 7.0.x, 7.3.x, and 8.1.x builds per ENISA EUVD-2026-26256 and SonicWall advisory SNWLID-2026-0004. No public exploit code has been identified and CISA SSVC classifies exploitation as none, placing this at lower operational priority despite the network-accessible attack vector.
Technical ContextAI
SonicOS is the proprietary operating system powering SonicWall next-generation firewalls, widely deployed as network perimeter devices in SMB and enterprise environments. CWE-121 (Stack-based Buffer Overflow) identifies the root cause: a memory write operation exceeds the allocated stack buffer, overwriting adjacent stack memory and triggering a process crash. The flaw is reachable over the network by an authenticated user with high-privilege access - consistent with the management-plane exposure typical of SonicOS administrative interfaces. The CPE cpe:2.3:a:sonicwall:sonicos:*:*:*:*:*:*:*:* covers the full SonicOS product line, with EUVD narrowing the affected range to specific builds: 7.0.1-5169 and older, 7.3.1-7013 and older, 8.1.0-8017 and older, and 6.5.5.1-6n and older. The overflow produces only availability impact - no memory disclosure or code execution path has been confirmed.
RemediationAI
Apply the vendor-issued patches documented in SonicWall advisory SNWLID-2026-0004 at https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2026-0004; upgrade to builds above SonicOS 7.0.1-5169, 7.3.1-7013, 8.1.0-8017, or 6.5.5.1-6n depending on your deployed release train. Exact patched version identifiers must be confirmed directly from the SonicWall advisory, as the available data specifies only the last-vulnerable builds. As an immediate compensating control, restrict management-plane access to the firewall to a minimal allowlist of trusted source IP addresses and dedicated management VLANs - this removes the network-reachable attack surface for this class of vulnerability without affecting data-plane traffic. Additionally, enforce multi-factor authentication on all SonicOS administrator accounts and audit for stale or over-privileged accounts to reduce the risk of credential compromise, which is the prerequisite for exploitation.
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Same weakness CWE-121 – Stack-based Buffer Overflow
View allSame technique Buffer Overflow
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External POC / Exploit Code
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