Race condition in Facebook Zstandard library

1) Race condition

EUVDB-ID: #VU50841

Risk: Low

CVSSv4.0: 4.4 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: N/A

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Exploit availability: No

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a race condition when creating files. The application creates a files with the default umask before chmod'ing to down to 0600. A local user can exploit the race and gain unauthorized access to sensitive information and escalate privileges on the system.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Zstandard: 1.0.0 - 1.4.8

CPE2.3

• cpe:2.3:a:facebook:zstd:1.0.0:*:*:*:*:*:*:*
• cpe:2.3:a:facebook:zstd:1.1.0:*:*:*:*:*:*:*
• cpe:2.3:a:facebook:zstd:1.1.1:*:*:*:*:*:*:*
• cpe:2.3:a:facebook:zstd:1.1.2:*:*:*:*:*:*:*
• cpe:2.3:a:facebook:zstd:1.1.3:*:*:*:*:*:*:*
• cpe:2.3:a:facebook:zstd:1.1.4:*:*:*:*:*:*:*
• cpe:2.3:a:facebook:zstd:1.2.0:*:*:*:*:*:*:*
• cpe:2.3:a:facebook:zstd:1.3.0:*:*:*:*:*:*:*
• cpe:2.3:a:facebook:zstd:1.3.1:*:*:*:*:*:*:*
• cpe:2.3:a:facebook:zstd:1.3.2:*:*:*:*:*:*:*

External links

https://github.com/facebook/zstd/issues/2491
https://github.com/facebook/zstd/commit/a774c5797399040af62db21d8a9b9769e005430e

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

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