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Vulnerabilities

Vulnerability · CVE-2020-5138

A Heap Overflow vulnerability in the SonicOS allows a remote unauthenticated attacker to cause Denial of Service (DoS) on the firewall SSLVPN service and leads to SonicOS crash.

Published Oct 12, 2020 · catalog updated Jun 17, 2026 · A Heap Overflow vulnerability

Last checked Nov 2, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2020-5138. EPSS is 1.77%. Act only if a listed version of A Heap Overflow vulnerability is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (A Heap Overflow vulnerability).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
1.77%
Remediation
Version ranges on file
Affected products
cpe sonicwall/sonicos · cpe sonicwall/sonicosv

A Heap Overflow vulnerability in the SonicOS allows a remote unauthenticated attacker to cause Denial of Service (DoS) on the firewall SSLVPN service and leads to SonicOS crash. This vulnerability affected SonicOS Gen 5 version 5.9.1.7, 5.9.1.13, Gen 6 version 6.5.4.7, 6.5.1.12, 6.0.5.3, SonicOSv 6.5.4.v and Gen 7 version SonicOS 7.0.0.0.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe sonicwall/sonicos7.0.0.0
  • cpe sonicwall/sonicos<= 5.9.1.13
  • cpe sonicwall/sonicos>= 6.0.0.0, <= 6.0.5.3
  • cpe sonicwall/sonicos>= 6.5.0.0, <= 6.5.1.11
  • cpe sonicwall/sonicos>= 6.5.4.0, <= 6.5.4.7
  • cpe sonicwall/sonicosv<= 6.5.4.4

How to fix CVE-2020-5138

  • Upgrade

    CVE-2020-5138 lists a fix boundary at 5.9.1.13. Compare the installed build with that boundary before you change production.

  • Version check

    Affected <= 5.9.1.13

  • Advisory

    Open the inventory_critical record and follow its fix.

  • Official advisories

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2020-5138. EPSS is 1.77%. Act only if a listed version of A Heap Overflow vulnerability is installed.

Which versions are affected?

Compare what you have installed with 7.0.0.0, <= 5.9.1.13, >= 6.0.0.0, <= 6.0.5.3, >= 6.5.0.0, <= 6.5.1.11, >= 6.5.4.0, <= 6.5.4.7, <= 6.5.4.4. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-122: Heap-based Buffer Overflow; CWE-787: Out-of-bounds Write. EPSS 1.77%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

SonicWall SonicOS security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 12, 2020 · Monitored products — critical

    Detected

    A Heap Overflow vulnerability in the SonicOS allows a remote unauthenticated attacker to cause Denial of Service (DoS) on the firewall SSLVPN service and leads to SonicOS crash. This vulnerability affected SonicOS Gen 5 version 5.9.1.7, 5.9.1.13, Gen 6 version 6.5.4.7, 6.5.1.12, 6.0.5.3, SonicOSv 6.5.4.v and Gen 7 version SonicOS 7.0.0.0.

  2. Jun 17, 2026 · Monitored products — critical

    Updated

    A Heap Overflow vulnerability in the SonicOS allows a remote unauthenticated attacker to cause Denial of Service (DoS) on the firewall SSLVPN service and leads to SonicOS crash. This vulnerability affected SonicOS Gen 5 version 5.9.1.7, 5.9.1.13, Gen 6 version 6.5.4.7, 6.5.1.12, 6.0.5.3, SonicOSv 6.5.4.v and Gen 7 version SonicOS 7.0.0.0.

Sources

  • Monitored products — criticalVendor advisoryCVE-2020-5138

    A Heap Overflow vulnerability in the SonicOS allows a remote unauthenticated attacker to cause Denial of Service (DoS) on the firewall SSLVPN service and leads to SonicOS crash. This vulnerability affected SonicOS Gen 5 version 5.9.1.7, 5.9.1.13, Gen 6 version 6.5.4.7, 6.5.1.12, 6.0.5.3, SonicOSv 6.5.4.v and Gen 7 version SonicOS 7.0.0.0.

    nvd.nist.gov

References

Freshness

Last verified in this catalog Nov 2, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • Monitored products — criticalNov 2, 2026