How severe is CVE-2018-12026?

CVE-2018-12026 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2018-12026 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (78th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-12026?

CVE-2018-12026 affects Phusion Passenger. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2018-12026?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2018-12026 published?

CVE-2018-12026 was published on 2018-06-17 and last updated on 2026-06-17.

CVE-2018-12026

CVE-2018-12026 is a critical-severity vulnerability in Phusion Passenger with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-59.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 2% (78th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-59
Affected product: Phusion Passenger
Published: 2018-06-17
Last modified: 2026-06-17

Description

During the spawning of a malicious Passenger-managed application, SpawningKit in Phusion Passenger 5.3.x before 5.3.2 allows such applications to replace key files or directories in the spawning communication directory with symlinks. This then could result in arbitrary reads and writes, which in turn can result in information disclosure and privilege escalation.

Frequently asked questions

What is CVE-2018-12026?: During the spawning of a malicious Passenger-managed application, SpawningKit in Phusion Passenger 5.3.x before 5.3.2 allows such applications to replace key files or directories in the spawning communication directory with symlinks. This then could result in arbitrary reads and writes, which in turn can result in information disclosure and privilege escalation.
How severe is CVE-2018-12026?: CVE-2018-12026 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2018-12026 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (78th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-12026?: CVE-2018-12026 affects Phusion Passenger. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2018-12026?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2018-12026 published?: CVE-2018-12026 was published on 2018-06-17 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:phusion:passenger:*:*:*:*:*:*:*:*

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