VulnerabilityPublished 4 Mar 2026

CVE-2026-3439: SonicWall SonicOS · Stack-based Buffer Overflow

Affects SonicWall SonicOSSource CVE Database V5

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Not known to be exploited · CVSS 4.9 Medium.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 3.1 base score

4.9Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.2% chance of exploitation in 30 days – higher than 18% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: High
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: High: The attacker is authorized with (i.e., requires) privileges that provide significant (e.g., administrative) control over the vulnerable component that could affect component-wide settings and files.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 4 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
SonicWallSonicOS	Affected =7.0.1-5169 and older versions =7.3.1-7013 and older versions =8.1.0-8017 and older versions	Fixed in–

AI-suggested

Organizations should immediately review their SonicWall firewall versions and identify devices running affected SonicOS versions (7.0.1-5169 and older, 7.3.1-7013 and older, 8.1.0-8017 and older). Until patches are released, mitigate risk by restricting administrative access to trusted networks and users only, enforcing strong authentication mechanisms such as multi-factor authentication, and monitoring for unusual authentication attempts or certificate-related errors. Network segmentation should be employed to limit access to firewall management interfaces. Implement strict credential management policies to reduce the risk of compromised accounts. Regularly audit firewall logs for signs of exploitation attempts. Once SonicWall releases patches addressing this vulnerability, prioritize immediate deployment. Additionally, consider deploying intrusion detection/prevention systems (IDS/IPS) tuned to detect anomalous certificate handling or buffer overflow attempts. Engage with SonicWall support for any available workarounds or hotfixes. Maintain up-to-date backups and incident response plans to recover quickly from potential DoS events.

Description

A post-authentication Stack-based Buffer Overflow vulnerability in SonicOS certificate handling allows a remote attacker to crash a firewall.

Impact

The primary impact of CVE-2026-3439 is a denial of service condition caused by crashing SonicWall firewalls. This can disrupt network security controls, potentially exposing internal networks to unauthorized access or attacks during downtime. Organizations relying on SonicWall devices for perimeter defense, VPN termination, or internal segmentation may experience significant operational disruption. The requirement for authentication limits exploitation to insiders or attackers who have compromised credentials, but this does not eliminate risk, especially in environments with weak credential management or exposed management interfaces. The vulnerability could also be leveraged as part of a multi-stage attack to gain further control if combined with other exploits. The widespread deployment of SonicWall devices in enterprise, government, and critical infrastructure sectors globally increases the potential scope of impact. Downtime of firewalls can lead to compliance violations, data breaches, and operational losses. The lack of known exploits in the wild currently reduces immediate risk but does not preclude future exploitation once exploit code becomes available.

CWE-121Stack-based Buffer Overflow (opens in a new tab)
Variant weaknessLikelihood of exploit: HighCWE Top 25 (2025): #14
The product writes past the end of a buffer that was allocated on the stack.
Operation · Build and Compilation · Environment Hardening
Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index…
Architecture and Design
Use an abstraction library to abstract away risky APIs. Not a complete solution.
Implementation
Implement and perform bounds checking on input.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

psirt.global.sonicwall.com/vuln-detail/SNWLID-2026-0001 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 4 Mar 2026, 09:47 UTC

WeaknessesCWE-121

Technical details

References

Community reviews

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