CVE-2026-40256 | Weblate: Prefix-Based Repository Boundary Check Bypass via Symlink/Junction Path Prefix Collision

Weblate is a web based localization tool. In versions prior to 5.17, repository-boundary validation relies on string prefix checks on resolved absolute paths. In multiple code paths, the check uses startswith against the repository root path. This is not path-segment aware and can be bypassed when the external path shares the same string prefix as the repository path (for example, repo and repo_outside). This issue has been fixed in version 5.17.

Published: 2026-04-15 Last update: 2026-04-21 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-40256 is rated Low Risk (24.2/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.04%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-40256

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-16 — 0.04% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-40256

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.0 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.1 1.4 [email protected]

Weakness enumeration for CVE-2026-40256

GitHub Security Advisory for CVE-2026-40256

GHSA-ffgh-3jrf-8wvh · Severity: medium · Ecosystem: pip — Weblate: Prefix-Based Repository Boundary Check Bypass via Symlink/Junction Path Prefix Collision

OS Trackers for CVE-2026-40256

vendor priority summary link
suse medium — https://www.suse.com/security/cve/CVE-2026-40256/

Affected software / configurations for CVE-2026-40256

Vendor Product Version Raw CPE
weblate weblate < 5.17 cpe:2.3:a:weblate:weblate:*:*:*:*:*:*:*:*

References for CVE-2026-40256

cvelogic Threat Intelligence