CVE-2020-5137: A buffer overflow vulnerability in SonicOS allows a remote unauthenticated attacker to cause Denial of Service (DoS) on the firewall SSLVPN

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

• sonicwall sonicosup to 5.9.1.13 inclusive
• sonicwall sonicos6.0.0.0 and later · up to 6.0.5.3 inclusive
• sonicwall sonicos6.5.0.0 and later · up to 6.5.1.11 inclusive
• sonicwall sonicos6.5.4.0 and later · up to 6.5.4.7 inclusive
• sonicwall sonicos7.0.0.0
• sonicwall sonicosvup to 6.5.4.4 inclusive

Versions reported by the vendor

Affected version ranges reported by the assigning authority (sonicwall). Independent of NVD's CPE analysis and usually ahead of it.

• SonicWall SonicOS

  • SonicOS 6.5.4.7-79n and earlier, SonicOS 5.9.1.7-2n and earlier, SonicOS 5.9.1.13-5n and earlier, SonicOS 6.5.1.11-4n and earlier, SonicOS 6.0.5.3-93o and earlier, SonicOSv 6.5.4.4-44v-21-794 and earlier, SonicOS 7.0.0.0-1affected

Other highest-scoring records for the same primary product.

• CVE-2024-53704An Improper Authentication vulnerability in the SSLVPN authentication mechanism allows a remote attacker to bypass authentication.KEV
  98Now
• CVE-2020-5135A buffer overflow vulnerability in SonicOS allows a remote attacker to cause Denial of Service (DoS) and potentially execute arbitrary code KEV
  77This week
• CVE-2024-40766An improper access control vulnerability has been identified in the SonicWall SonicOS management access, potentially leading to unauthorizedKEV
  75This week

Published before and after this one in the same product

• ← EarlierCVE-2020-5134Oct 12, 2020 · A vulnerability in SonicOS allows an authenticated attacker to cause out-of-bound invalid file reference leads to a firewall crash.
  26Monitor
• ← EarlierCVE-2020-5136Oct 12, 2020 · A buffer overflow vulnerability in SonicOS allows an authenticated attacker to cause Denial of Service (DoS) in the SSL-VPN and virtual assi
  26Monitor
• Later →CVE-2020-5138Oct 12, 2020 · A Heap Overflow vulnerability in the SonicOS allows a remote unauthenticated attacker to cause Denial of Service (DoS) on the firewall SSLVP
  31Monitor

Root cause

When data is copied, the source length is not compared with the size of the destination buffer. Excess data overwrites adjacent memory.

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

1char buf[256];2memcpy(buf, pkt->data, pkt->len);

1char buf[256];2if (pkt->len > sizeof(buf)) {3  return -EINVAL;4}5memcpy(buf, pkt->data, pkt->len);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.