A privilege escalation vulnerability existed in the Below service prior to v0.9.0 due to the creation of a world-writable directory at…

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.

Scores

EPSS (exploitation in 30 days)

0.37% · top 69% of all CVEs (7 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: total

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.8.

Weakness

• Incorrect Permission Assignment for Critical Resource (CWE-732)
• CWE-732 (opens in a new tab)All about CWE-732 and its CVEs

Affected products

• Meta Platforms, Inc · below

  • affected 0.0.0 – < 0.9.0

Affected packages

From reviewed advisories of the GitHub Advisory Database.

• crates.iobelowGHSA-9mc5-7qhg-fp3w (opens in a new tab)

References (3)

• https://www.facebook.com/security/advisories/cve-2025-27591 (opens in a new tab)x_refsource_CONFIRM
• https://github.com/facebookincubator/below/commit/da9382e6e3e332fd2c3195e22f34977f83f0f1f3 (opens in a new tab)x_refsource_MISC
• http://www.openwall.com/lists/oss-security/2025/03/12/1 (opens in a new tab)

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisory GHSA-9mc5-7qhg-fp3w (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2025-27591](https://trackcve.app/badge/CVE-2025-27591.svg)](https://trackcve.app/cve/CVE-2025-27591)

Record last updated 21 Mar 2025, 20:38 UTC.