Pagy I18n locale option is not validated before being used in a file path

published 2026-07-28 3 mo ago modified 2026-10-23 16 d ago also GHSA-2xmw-f8j8-wfxc , EUVD-2026-50088

cvss: 6.9; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 30%
public exploits: 0; none known

Pagy is agnostic pagination in plain Ruby. From 43.0.0 until 43.5.6, Pagy::I18n.locale= in gem/lib/pagy/modules/i18n/i18n.rb stored locale values verbatim and later used them as <locale>.yml path components, allowing untrusted params[:locale] values with absolute paths or ../ sequences to create a file existence and readability oracle for YAML files. This issue is fixed in version 43.5.6.

Patch / fix

fixed in 1 links 3

rubygems pagy 43.5.6

github.com/ddnexus/pagy@efcf096 commit
github.com/ddnexus/pagy#908 pull request
github.com/ddnexus/pagy/releases/tag/43.5.6 release

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: partial
Assessed: 3 mo ago (2026-07-29)

Exploit prediction

0.37% chance of exploitation in the next 30 days, higher than 30% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/ddnexus/pagy/security/advisories/GHSA-2xmw-f8j8-wfxc referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	6.9	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
CNA	4.0	6.9	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected packages

ecosystem	package	affected	fixed in
rubygems	pagy	>=43.0.0, <43.5.6	43.5.6

Affected products

ddnexus pagy

Classification

Weakness

CWE-22 Improper Limitation of a Pathname to a Restricted Directory
CWE-200 Exposure of Sensitive Information to an Unauthorized Actor

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary