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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTNIST
6.8 MEDIUM
LOCAL
LOW
NONE
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N
facebookCNA
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CVEADP
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CISA-ADPADP
6.8 MEDIUM
LOCAL
LOW
NONE
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: 5%
VendorProductVersion
facebookbelow
𝑥
< 0.9.0
𝑥
= Vulnerable software versions
Common Weakness Enumeration
References
https://github.com/facebookincubator/below/commit/da9382e6e3e332fd2c3195e22f34977f83f0f1f3
https://www.facebook.com/security/advisories/cve-2025-27591
http://www.openwall.com/lists/oss-security/2025/03/12/1