What’s Vulnerable › Vulnerabilities

CVE-2019-9949

• Severity: high (CVSS 8.8 v3.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.0% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2019-05-23 · updated 2026-06-17
• Weakness: CWE-59

Description

Western Digital My Cloud Cloud, Mirror Gen2, EX2 Ultra, EX2100, EX4100, DL2100, DL4100, PR2100 and PR4100 before firmware 2.31.183 are affected by a code execution (as root, starting from a low-privilege user session) vulnerability. The cgi-bin/webfile_mgr.cgi file allows arbitrary file write by abusing symlinks. Specifically, this occurs by uploading a tar archive that contains a symbolic link, then uploading another archive that writes a file to the link using the "cgi_untar" command. Other commands might also be susceptible. Code can be executed because the "name" parameter passed to the cgi_unzip command is not sanitized.

Affected products

• Westerndigital My Cloud Dl2100 Firmware: before 2.31.183 — fixed in 2.31.183
• Westerndigital My Cloud Dl4100 Firmware: before 2.31.183 — fixed in 2.31.183
• Westerndigital My Cloud Ex2100 Firmware: before 2.31.183 — fixed in 2.31.183
• Westerndigital My Cloud Ex2 Ultra Firmware: before 2.31.183 — fixed in 2.31.183
• Westerndigital My Cloud Ex4100 Firmware: before 2.31.183 — fixed in 2.31.183
• Westerndigital My Cloud Firmware: before 2.31.183 — fixed in 2.31.183
• Westerndigital My Cloud Mirror Gen2 Firmware: before 2.31.183 — fixed in 2.31.183
• Westerndigital My Cloud Pr2100 Firmware: before 2.31.183 — fixed in 2.31.183
• Westerndigital My Cloud Pr4100 Firmware: before 2.31.183 — fixed in 2.31.183

How to fix

Upgrade to a fixed version: Westerndigital My Cloud Dl2100 Firmware 2.31.183; Westerndigital My Cloud Dl4100 Firmware 2.31.183; Westerndigital My Cloud Ex2100 Firmware 2.31.183; Westerndigital My Cloud Ex2 Ultra Firmware 2.31.183; Westerndigital My Cloud Ex4100 Firmware 2.31.183; Westerndigital My Cloud Firmware 2.31.183; Westerndigital My Cloud Mirror Gen2 Firmware 2.31.183; Westerndigital My Cloud Pr2100 Firmware 2.31.183; Westerndigital My Cloud Pr4100 Firmware 2.31.183. Check the vendor advisory for mitigations.

References

• https://bnbdr.github.io/posts/wd/
• https://community.wd.com/t/new-release-my-cloud-firmware-versions-2-31-183-05-20-2019/237717
• https://github.com/bnbdr/wd-rce/
• https://bnbdr.github.io/posts/wd/
• https://community.wd.com/t/new-release-my-cloud-firmware-versions-2-31-183-05-20-2019/237717
• https://github.com/bnbdr/wd-rce/

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