How severe is CVE-2026-34763?

CVE-2026-34763 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 low, integrity none, and availability none.

Is CVE-2026-34763 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (15th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-34763?

CVE-2026-34763 affects Rack. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-34763?

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

Does CVE-2026-34763 have an EU (EUVD) identifier?

Yes. CVE-2026-34763 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-18380.

When was CVE-2026-34763 published?

CVE-2026-34763 was published on 2026-04-02 and last updated on 2026-06-17.

CVE-2026-34763

CVE-2026-34763 is a medium-severity vulnerability in Rack 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-625.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
EPSS exploit prediction: 0% (15th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-18380
Weakness: CWE-625
Affected product: Rack
Published: 2026-04-02
Last modified: 2026-06-17

Description

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Directory interpolates the configured root path directly into a regular expression when deriving the displayed directory path. If root contains regex metacharacters such as +, *, or ., the prefix stripping can fail and the generated directory listing may expose the full filesystem path in the HTML output. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.

Frequently asked questions

What is CVE-2026-34763?: Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Directory interpolates the configured root path directly into a regular expression when deriving the displayed directory path. If root contains regex metacharacters such as +, *, or ., the prefix stripping can fail and the generated directory listing may expose the full filesystem path in the HTML output. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.
How severe is CVE-2026-34763?: CVE-2026-34763 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 low, integrity none, and availability none.
Is CVE-2026-34763 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (15th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-34763?: CVE-2026-34763 affects Rack. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-34763?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-34763 have an EU (EUVD) identifier?: Yes. CVE-2026-34763 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-18380.
When was CVE-2026-34763 published?: CVE-2026-34763 was published on 2026-04-02 and last updated on 2026-06-17.

References

https://github.com/rack/rack/security/advisories/GHSA-7mqq-6cf9-v2qp

Affected products (1)

cpe:2.3:a:rack:rack:*:*:*:*:*:ruby:*:*

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