A race condition in the nginx module in Phusion Passenger 3.x through 5.x before 5.3.2 allows local escalation of privileges when a non-stan
A race condition in the nginx module in Phusion Passenger 3.x through 5.x before 5.3.2 allows local escalation of privileges when a non-standard passenger_instance_registry_dir with insufficiently strict permissions is configured. Replacing a file with a symlink after the file was created, but before it was chowned, leads to the target of the link being chowned via the path. Targeting sensitive files such as root's crontab file allows privilege escalation.
- Published
- Jun 17, 2018
- Updated
- Jun 16, 2026
- EPSS
- 0.3% · 18th percentile
- CWE
- CWE-362
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Report tools
Action score
28
Monitor
Low priority for now.
- CVSS
- 28 / 40 · 7.0 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.3%
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpAffected systems
| Vendor | Product | CPE |
|---|---|---|
| phusion | passenger | cpe:2.3:a:phusion:passenger |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- debian debian linux8.0
- phusion passenger3.0.0 and later · before 5.3.2
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | passenger | before 5.0.30-1.1 | 5.0.30-1.1 |
| Debian:8 | ruby-passenger | before 4.0.53-1+deb8u1 | 4.0.53-1+deb8u1 |
| RubyGems | passenger | from 3.0.0 · before 5.3.2 | 5.3.2 |
| SUSE:Linux Enterprise Module for Containers 12 | rubygem-passenger | before 5.0.18-12.9.1 | 5.0.18-12.9.1 |
Same product
phusion: all recordsOther highest-scoring records for the same primary product.
- CVE-2018-12026During the spawning of a malicious Passenger-managed application, SpawningKit in Phusion Passenger 5.3.x before 5.3.2 allows such applicatio40Plan
- CVE-2018-12027An Insecure Permissions vulnerability in SpawningKit in Phusion Passenger 5.3.x before 5.3.2 causes information disclosure in the following 35Monitor
- CVE-2012-6135RubyGems passenger 4.0.0 betas 1 and 2 allows remote attackers to delete arbitrary files during the startup process.31Monitor
- CVE-2018-12028An Incorrect Access Control vulnerability in SpawningKit in Phusion Passenger 5.3.x before 5.3.2 allows a Passenger-managed malicious applic31Monitor
- CVE-2016-10345In Phusion Passenger before 5.1.0, a known /tmp filename was used during passenger-install-nginx-module execution, which could allow local a31Monitor
- CVE-2025-26803The http parser in Phusion Passenger 6.0.21 through 6.0.25 before 6.0.26 allows a denial of service during parsing of a request with an inva30Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| debian:passenger | 5.0.30-1.1 · Debian:12 | Package registry (OSV) |
| debian:ruby-passenger | 4.0.53-1+deb8u1 · Debian:8 | Package registry (OSV) |
| RubyGems:passenger | 5.3.2 | Package registry (OSV) |
| suse:rubygem-passenger | 5.0.18-12.9.1 · SUSE:Linux Enterprise Module for Containers 12 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- A low-privileged account is enough.
- No user action is required.
- Special conditions such as timing or configuration are required.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- High
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-362 · Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')CVSS vector
CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
—
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- blog.phusion.nl/passenger-5-3-2
- lists.debian.org/debian-lts-announce/2018/06/msg00007.html
- pulsesecurity.co.nz/advisories/phusion-passenger-priv-esc
- security.gentoo.org/glsa/201807-02
Vendor advisories and official records. Exploit/PoC links are deliberately left out.