How severe is CVE-2026-3439?

CVE-2026-3439 has a CVSS 3.x base score of 4.9, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-3439 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (17th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-3439?

CVE-2026-3439 affects Sonicwall Sonicos. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-3439?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-3439 have an EU (EUVD) identifier?

Yes. CVE-2026-3439 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-9387.

When was CVE-2026-3439 published?

CVE-2026-3439 was published on 2026-03-04 and last updated on 2026-06-17.

CVE-2026-3439

CVE-2026-3439 is a medium-severity vulnerability in Sonicwall Sonicos with a CVSS 3.x base score of 4.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-121.

Key facts

Severity: Medium (CVSS 3.x base score 4.9)
EPSS exploit prediction: 0% (17th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-9387
Weakness: CWE-121
Affected product: Sonicwall Sonicos
Published: 2026-03-04
Last modified: 2026-06-17

Description

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

Frequently asked questions

What is CVE-2026-3439?: A post-authentication Stack-based Buffer Overflow vulnerability in SonicOS certificate handling allows a remote attacker to crash a firewall.
How severe is CVE-2026-3439?: CVE-2026-3439 has a CVSS 3.x base score of 4.9, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-3439 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (17th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-3439?: CVE-2026-3439 affects Sonicwall Sonicos. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-3439?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-3439 have an EU (EUVD) identifier?: Yes. CVE-2026-3439 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-9387.
When was CVE-2026-3439 published?: CVE-2026-3439 was published on 2026-03-04 and last updated on 2026-06-17.

References

https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2026-0001

Affected products (1)

cpe:2.3:o:sonicwall:sonicos:*:*:*:*:*:*:*:*

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