Arbitrary file overwrite in Open Container Initiative umoci

Published: 2021-04-07
Risk Medium
Patch available YES
Number of vulnerabilities 1
CVE ID CVE-2021-29136
Exploitation vector Network
Public exploit N/A
Vulnerable software
Other software / Other software solutions


Security Advisory

This security advisory describes one medium risk vulnerability.

1) UNIX symbolic link following

Risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C] [PCI]

CVE-ID: CVE-2021-29136

CWE-ID: CWE-61 - UNIX Symbolic Link (Symlink) Following

Exploit availability: No


The vulnerability allows a remote attacker to compromise the affected system.

The vulnerability exists due to a symlink following issue when processing crafted images. A remote attacker can create a specially crafted image with symbolic link to a critical file on the system and overwrite it, when "umoci unpack" or "umoci raw unpack" is used.

Successful exploitation of this vulnerability may result in privilege escalation.


Install updates from vendor's website.

Vulnerable software versions

umoci: 0.4.0, 0.4.1, 0.4.2, 0.4.3, 0.4.4, 0.4.5, 0.4.6

CPE External links

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.