CVE-2025-27591

Description

A privilege escalation vulnerability existed in the Below service prior to v0.9.0 due to the creation of a world-writable directory at /var/log/below. This could have allowed local unprivileged users to escalate to root privileges through symlink attacks that manipulate files such as /etc/shadow.

CVSS v3.1 Score

6.8

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N

Weakness Type (CWE)

CWE-732 CWE-732

Affected Products

Vendor	Product	Versions
facebook	below	< 0.9.0

References

Advisories & Patches

https://github.com/facebookincubator/below/commit/da9382e6e3e332fd2c3195e22f34977f83f0f1f3 https://www.facebook.com/security/advisories/cve-2025-27591

Exploits

http://www.openwall.com/lists/oss-security/2025/03/12/1

Frequently Asked Questions

What is CVE-2025-27591? +

A privilege escalation vulnerability existed in the Below service prior to v0.9.0 due to the creation of a world-writable directory at /var/log/below. This could have allowed local unprivileged users to escalate to root privileges through symlink attacks that manipulate files such as /etc/shadow. It has a CVSS v3.1 base score of 6.8 (MEDIUM).

How severe is CVE-2025-27591? +

CVE-2025-27591 has a CVSS v3.1 score of 6.8 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-27591? +

CVE-2025-27591 affects products from facebook, specifically: below. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-27591? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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