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CVE-2026-125109

4.8 mediumEPSS 0.2%

Medium (4.8) in rack rack. EPSS 0.2% estimated probability of exploitation activity in the next 30 days.

On this page
Rack is a modular Ruby web server interface. From 3.0 until 3.1.23 and 3.2.8, Rack::Request#host_with_port, #base_url, and #url can return an attacker-controlled invalid authority from Host, X-Forwarded-Host, or Forwarded: host= verbatim. Applications without an independent host allowlist that use these methods for absolute URLs, redirects, or origin-dependent checks can emit attacker-chosen delimiters, enabling redirect manipulation, string-based allowlist bypass, or unescaped markup reflection. Rails overrides these methods and is not expected to be affected. This issue is fixed in versions 3.1.23 and 3.2.8.

Severity

CVSS 3.1

4.8 medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
EPSS
0.2% estimated probability of exploitation activity in the next 30 days; 13th percentile. Scored 2026-11-10. A forecast for this CVE across the internet, not for your own systems.
CISA's assessment (SSVC)
Exploitation: none · Automatable: no · Technical impact: partial, assessed 2026-11-10. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
CWE
CWE-1286 Improper Validation of Syntactic Correctness of Input
Published
Modified
Assigned by
GitHub_M (CNA)
NVD analysis
Not in the NVD yet
Record from
the CVE List, synced

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Affected

Versions

From the CNA's record in the CVE List.

ProductAffected
rack>= 3.0, < 3.1.23
rack>= 3.2, < 3.2.8

Linux distributions

DistributionReleasePackageFixed inAdvisory
Debian12, 13ruby-rackno fix listedDEBIAN-CVE-2026-125109
Debian14ruby-rack3.2.8-1DEBIAN-CVE-2026-125109

From the distributions' data via OSV.dev: the Debian Security Tracker. Modified: reformatted and linked to CVE records. Credits. On the distributions' own pages: Debian.

Attack patterns (CAPEC)

  • CAPEC-66 SQL Injection Likelihood: High · Severity: High
  • CAPEC-676 NoSQL Injection Likelihood: High · Severity: High

The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.

References

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