CVE-2025-27591
MEDIUMBelow has Incorrect Permission Assignment for Critical Resource
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
belowReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | below | all versions | 0.9.0 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
BridgerAlderson/CVE-2025-27591-PoC
CVE-2025-27591 is a privilege escalation vulnerability that affected the
0x00Jeff/CVE-2025-27591
self cleaning CVE-2025-27591 Poc that grants a root reverse shell instea
obamalaolu/CVE-2025-27591
CVE-2025-27591
dollarboysushil/Linux-Privilege-Escalation-CVE-2025-27591
CVE-2025-27591 is a known privilege escalation vulnerability in the Belo
incommatose/CVE-2025-27591-PoC
A Proof of Concept for CVE-2025-27591, a local privilege escalation in B
rvzsec/CVE-2025-27591
Below v0.8.1 - Local Privilege Escalation (CVE-2025-27591) - PoC Exploit
Cythonic1/CVE-2025-27591
a C exploit for CVE-2025-27591, which allow an attacker to escalate priv
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for below. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update below to 0.9.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-27591 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2025-27591 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2025-27591. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-27591 in your dependencies?
O3 detects CVE-2025-27591 across crates.io dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.