How severe is CVE-2025-26803?

CVE-2025-26803 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.

Is CVE-2025-26803 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (43rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-26803?

CVE-2025-26803 affects Phusion Passenger. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-26803?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2025-26803 have an EU (EUVD) identifier?

Yes. CVE-2025-26803 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-4281.

When was CVE-2025-26803 published?

CVE-2025-26803 was published on 2025-02-24 and last updated on 2026-06-17.

CVE-2025-26803

CVE-2025-26803 is a medium-severity vulnerability in Phusion Passenger with a CVSS 3.x base score of 5.3. 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-908.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
EPSS exploit prediction: 1% (43rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-4281
Weakness: CWE-908
Affected product: Phusion Passenger
Published: 2025-02-24
Last modified: 2026-06-17

Description

The 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 invalid HTTP method.

Frequently asked questions

What is CVE-2025-26803?: The 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 invalid HTTP method.
How severe is CVE-2025-26803?: CVE-2025-26803 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.
Is CVE-2025-26803 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (43rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-26803?: CVE-2025-26803 affects Phusion Passenger. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-26803?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-26803 have an EU (EUVD) identifier?: Yes. CVE-2025-26803 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-4281.
When was CVE-2025-26803 published?: CVE-2025-26803 was published on 2025-02-24 and last updated on 2026-06-17.

References

Affected products (1)

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

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