CVE-2020-5135 SonicWall SonicOS: memory-safety flaw
In plain words: The program mishandles the memory it uses to keep track of data. A specially made input can scramble that memory. Usually lets an attacker crash the program or run their own code with its permissions.
Confirmed exploited by CISA on · US federal patch deadline Apr 5, 2022
What to do
- Install SonicWall's security update for SonicOS. If no update exists, follow the vendor's workaround or stop using the product until one ships.
- Patch edge devices first — attackers often start scanning for them within hours of a fix.
- Never expose the device's admin page to the internet.
- After patching a device that was exposed, follow the vendor's compromise checks, end active sessions and change passwords.
Who is affected
Work IT. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.
What's at risk: They face the internet and guard the whole network, so a flaw here can hand attackers a way in — and these devices usually run no antivirus, so break-ins go unnoticed.
The details
- Official name
- SonicWall SonicOS Buffer Overflow Vulnerability
- Product
- SonicWall SonicOS
- CISA 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.
- Type of flaw
- Memory-safety flaw (CWE-120)
- Confirmed exploited
- Mar 15, 2022 — known to be used in ransomware attacks
- US federal patch deadline
- Apr 5, 2022
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Answering about CVE-2020-5135 ·
Questions about CVE-2020-5135
Is CVE-2020-5135 being exploited?
Yes. CISA added CVE-2020-5135 to its Known Exploited Vulnerabilities catalog on Mar 15, 2022, which means there is reliable evidence of real-world attacks, including by ransomware groups.
How do I fix CVE-2020-5135?
Install SonicWall's security update for SonicOS. If no update exists, follow the vendor's workaround or stop using the product until one ships. Patch edge devices first — attackers often start scanning for them within hours of a fix.
Am I affected by CVE-2020-5135?
Only if you use SonicWall SonicOS. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.