CVE-2026-109595
Description
A flaw was found in Hugo. This vulnerability allows an attacker to cause unauthorized information disclosure through path traversal when processing untrusted themes or modules. By supplying relative file paths or symbolic links that reference locations outside the project directory, an attacker can cause arbitrary files readable by the build user to be incorporated into the published output during asset compilation.
Statement
A flaw was found in Hugo's asset compilation pipeline. When compiling themes or modules, the ESBuild fallback resolver utilized in functions such as js.Build, js.Batch, and css.Build fails to prevent path traversal when handling crafted relative imports or symbolic links. An attacker who convinces a user or automated CI/CD pipeline to build a site containing a malicious theme can leak arbitrary host files readable by the build user into the published CSS or JavaScript output.
Mitigation
Avoid compiling Hugo sites with untrusted themes or third-party modules. When processing unverified assets, execute builds within an isolated, unprivileged container environment with minimal directory mounts and read-only host access.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | N/A | 5.5 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | Required | N/A | Required |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | None | N/A | None |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
cve.org: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
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