Cyber Resilience

CVE-2026-40256

Path Traversal in Weblate ≤ 5.17

Path Traversal
Published
15 April 2026
Modified
21 April 2026
Patch / advisory
View advisory
CVSS Score v3.1 5.0
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N
EPSS Score 0.0032 25th percentile
Risk Priority 35 floored blend · peak EPSS

Summary

CVE-2026-40256 is a medium-severity Path Traversal (CWE-22) vulnerability in Weblate Weblate. Its CVSS base score is 5.0 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 25th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A01:2025 Broken Access Control

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)
CWE-22

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1005 Data from Local System Collection
Adversaries may search local system sources, such as file systems, configuration files, local databases, virtual machine files, or process memory, to find files of interest and sensitive data prior to Exfiltration.
attack.mitre.org →
Why these techniques?

Path traversal in public-facing web app (CWE-22) directly enables remote exploitation for unauthorized local file access.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2026-33220Same product: Weblate Weblate
CVE-2026-34242Same product: Weblate Weblate
CVE-2025-68398Same product: Weblate Weblate
CVE-2025-68279Same product: Weblate Weblate
CVE-2026-23535Same vendor: Weblate
CVE-2025-6795Shared CWE-22
CVE-2026-25328Shared CWE-22
CVE-2025-11849Shared CWE-22
CVE-2026-27442Shared CWE-22
CVE-2025-25163Shared CWE-22

Affected Assets

weblate
weblate
≤ 5.17

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • SI-10 Information Input Validation
  • AC-3 Access Enforcement
  • AC-4 Information Flow Enforcement
Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V5.3.2

Mitigating Controls (NIST 800-53 r5) AI

SI-10 Information Input Validation good match
prevent

Directly requires validation of file/path inputs to reject traversals that bypass string-prefix checks on repository roots.

AC-3 Access Enforcement good match
prevent

Enforces access decisions on repository resources using segment-aware boundary checks rather than vulnerable prefix comparisons.

AC-4 Information Flow Enforcement partial match
prevent

Controls information flows between repository paths and external locations, mitigating improper boundary enforcement.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-02 partial match
prevents

Patching/maintenance can remediate known path-traversal flaws in deployed software (partial prevention of exploitability) but does nothing to stop the coding defect from being introduced in the first place.

PR.AA-05 none match
prevents

PR.AA-05 defines and reviews access policies but does not address code-level pathname neutralization, so neither direction prevents CWE-22.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
detects

Security testing in development catches path traversal via static/dynamic analysis.

A.8.25 Secure development life cycle partial match
prevents

Secure SDLC mandates input validation and path sanitization that directly prevent path traversal.

A.8.26 Application security requirements partial match
prevents

Application security requirements include rules for safe file handling and canonicalization.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles require least-privilege file access and directory isolation.

A.8.28 Secure coding partial match
prevents

Secure coding standards explicitly forbid unsafe path construction and mandate safe APIs.

A.8.3 Information access restriction partial match
mitigates

Information access restriction limits which files an application may read or write.

References