# omniauth-apple allows attacker to fake their email address during authentication

Advisory record · `GHSA-49r3-2549-3633`

- **Identifiers:** `GHSA-49r3-2549-3633` · `CVE-2020-26254`
- **State:** Confirmed
- **Severity:** CVSS 7.7 High
- **Critical:** No
- **Weakness (CWE):** [CWE-290](https://cwe.mitre.org/data/definitions/290.html)
- **Tags:** [Authentication bypass](https://agentprime.io/advisories/tag/auth-bypass.md)
- **Published:** 8 Dec 2020
- **Updated:** 10 Sept 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 8 Dec 2020, 14:18 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `omniauth-apple` (RubyGems): affected `<1.0.1`; fixed in `1.0.1`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> The omniauth-apple RubyGems package, versions before 1.0.1, lets an attacker set the info.email value during Apple sign-in to any value they choose, including another user's email address. This affects applications that use info.email to identify users; applications that identify users by uid are not affected in the same way. Upgrade to omniauth-apple 1.0.1 or later.

Written 8 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 7.7 High, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.013, the 71st percentile, on 9 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 15:16 UTC: First seen by agentprime
- 31 Oct 2026, 15:16 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-49r3-2549-3633)

## Sources

- [GitHub Advisory Database: GHSA-49r3-2549-3633](https://github.com/advisories/GHSA-49r3-2549-3633)
- [OSV: GHSA-49r3-2549-3633](https://osv.dev/vulnerability/GHSA-49r3-2549-3633)
- <https://github.com/nhosoya/omniauth-apple/security/advisories/GHSA-49r3-2549-3633>
- <https://nvd.nist.gov/vuln/detail/CVE-2020-26254>
- <https://github.com/nhosoya/omniauth-apple/commit/b37d5409213adae2ca06a67fec14c8d3d07d9016>
- <https://github.com/nhosoya/omniauth-apple>
- <https://github.com/nhosoya/omniauth-apple/blob/master/CHANGELOG.md#101---2020-12-03>
- <https://github.com/rubysec/ruby-advisory-db/blob/master/gems/omniauth-apple/CVE-2020-26254.yml>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-49r3-2549-3633>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-49r3-2549-3633/>. Everything for agents: <https://agentprime.io/llms.txt>.