CVE-2026-100690 — Gohugoio
HIGHCVE-2026-100690 is a high-severity (CVSS 7.5) CWE-59 vulnerability. No vendor fix is recorded yet; mitigation options are listed below.
Hugo versions from v0.161.0 through v0.165.0 run Node.js tools (css.PostCSS, css.TailwindCSS, js.Babel) under the Node.js permission model to restrict file system reads to the project…
Description
Hugo versions from v0.161.0 through v0.165.0 run Node.js tools (css.PostCSS, css.TailwindCSS, js.Babel) under the Node.js permission model to restrict file system reads to the project directory and configured mounts. Because the Node.js permission model validates only the lexical path and follows symbolic links that point outside the allowed set, Hugo did not detect symlinks escaping the sandbox. An attacker who can contribute content to a Hugo project (for example via a pull request) can commit a symlink such as assets/css/x.css -> /etc/passwd together with a PostCSS plugin that reads it, allowing any file readable by the Hugo build process to be disclosed and potentially embedded in the published site. This affects builds using the default security configuration; projects that do not invoke Node.js tools are unaffected. Fixed in v0.166.0, which scans allowed paths and fails the build when a symbolic link resolves outside them.
Detection & mitigation playbook
VulnerabilityDetect
Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`). Because exploitation targets the running service rather than your application code, O3 also flags the exploit behaviour from runtime telemetry and egress traffic.
Remediation status
No fixed release is recorded for CVE-2026-100690 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands. O3's runtime protection blocks the cwe-59 flaw at execution, which holds the line on hosts you cannot patch immediately.
How O3 protects you
O3 detects and blocks CVE-2026-100690 exploitation at runtime with eBPF exploit-chain detection, plus L7 egress monitoring that catches a post-exploitation callback and cuts the attacker's outbound channel.
Tailored to CVE-2026-100690. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-100690 in your dependencies?
O3 Security finds CVE-2026-100690 across dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.