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Vulnerabilities

Vulnerability · CVE-2026-34785

Rack is a modular Ruby web server interface.

Published Apr 2, 2026 · catalog updated Jul 24, 2026 · Rack is a modular

Check if you run it

No confirmed exploitation is on record for CVE-2026-34785. EPSS is 0.52%. Act only if a listed version of Rack is a modular is installed.

Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.52%
Remediation
Advisory link
Affected products
cpe rack/rack

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Static determines whether a request should be served as a static file using a simple string prefix check. When configured with URL prefixes such as "/css", it matches any request path that begins with that string, including unrelated paths such as "/css-config.env" or "/css-backup.sql". As a result, files under the static root whose names merely share the configured prefix may be served unintentionally, leading to information disclosure. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe rack/rackversion unspecified

How to fix CVE-2026-34785

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-34785. EPSS is 0.52%. Act only if a listed version of Rack is a modular is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-187; CWE-200: Exposure of Sensitive Information; CWE-552: Files or Directories Accessible to External Parties. EPSS 0.52%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Apr 2, 2026 · NIST NVD

    Detected

    Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Static determines whether a request should be served as a static file using a simple string prefix check. When configured with URL prefixes such as "/css", it matches any request path that begins with that string, including unrelated paths such as "/css-config.env" or "/css-backup.sql". As a result, fil

  2. Jul 24, 2026 · NIST NVD

    Updated

    Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Static determines whether a request should be served as a static file using a simple string prefix check. When configured with URL prefixes such as "/css", it matches any request path that begins with that string, including unrelated paths such as "/css-config.env" or "/css-backup.sql". As a result, fil

Sources

  • CVE.orgVulnerability recordCVE-2026-34785

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-34785

    30-day exploitation probability 0.5%

    first.org
  • NIST NVDVulnerability recordCVE-2026-34785

    Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Static determines whether a request should be served as a static file using a simple string prefix check. When configured with URL prefixes such as "/css", it matches any request path

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.