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CVE-2020-5135

SonicWall SonicOS Buffer Overflow

9.8 CRITICALActively exploited (CISA KEV)Used in ransomwareEPSS 26.9%
  1. Published12 Oct 2020
  2. Added to CISA KEV15 Mar 2022
  3. Remediation due5 Apr 2022
Actively exploited (CISA KEV)

A buffer overflow vulnerability in SonicOS allows a remote attacker to cause Denial of Service (DoS) and potentially execute arbitrary code by sending a malicious request to the firewall.

Added to KEV: 15 Mar 2022Federal remediation due: 5 Apr 2022Used in ransomware

Description

A buffer overflow vulnerability in SonicOS allows a remote attacker to cause Denial of Service (DoS) and potentially execute arbitrary code by sending a malicious request to the firewall. This vulnerability affected SonicOS Gen 6 version 6.5.4.7, 6.5.1.12, 6.0.5.3, SonicOSv 6.5.4.v and Gen 7 version 7.0.0.0.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

SonicWall Sonicos≥ 6.5.0.0 ≤ 6.5.1.11 · ≥ 6.5.4.0 ≤ 6.5.4.7 · ≤ 6.0.5.3 · 7.0.0.0
SonicWall Sonicosv≤ 6.5.4.4

Remediation

No fixed version is recorded in the NVD data. Check the vendor advisory for the latest guidance.

References

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Frequently asked

Is CVE-2020-5135 being actively exploited?

Yes. CVE-2020-5135 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 15 Mar 2022. It has been used in ransomware campaigns.

How severe is CVE-2020-5135?

CVE-2020-5135 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 26.9% probability of exploitation.

Which products are affected by CVE-2020-5135?

Affected products include SonicWall Sonicos, SonicWall Sonicosv.

How do I fix CVE-2020-5135?

Apply the vendor's patch or advisory guidance, then verify no affected versions remain across your devices.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2020-5135 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, Secuno flags any affected asset as top-priority automatically. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.