# Unverified Sign in with Apple callback parameter can override verified ID token claims

Advisory record · `GHSA-9fr5-g44g-9526`

- **Identifiers:** `GHSA-9fr5-g44g-9526` · `CVE-2026-117656` · `EEF-CVE-2026-117656`
- **State:** Confirmed
- **Severity:** CVSS 9.3 Critical
- **Critical:** Yes: CVSS 9+
- **Weakness (CWE):** [CWE-290](https://cwe.mitre.org/data/definitions/290.html) · [CWE-349](https://cwe.mitre.org/data/definitions/349.html)
- **Tags:** [Authentication bypass](https://agentprime.io/advisories/tag/auth-bypass.md) · [CWE-349](https://agentprime.io/advisories/tag/cwe-349.md)
- **Published:** 30 Oct 2026
- **Updated:** 31 Oct 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 30 Oct 2026, 23:55 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Critical

Critical, because:

- CVSS score 9.3: 9.0 or more.

How we decide what’s critical: <https://agentprime.io/advisories/critical.md>

## Affected packages

- `assent` (Hex): affected `>=0.1.25, <0.3.2`; fixed in `0.3.2`

## 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

- 9.3 Critical, CVSS 4.0: `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N`, from CNA (EEF)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0023, the 13th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 30 Oct 2026, 23:55 UTC: [Confirmed by the CVE List](https://www.cve.org/CVERecord?id=CVE-2026-117656)
- 31 Oct 2026, 00:16 UTC: [Confirmed by NVD](https://nvd.nist.gov/vuln/detail/CVE-2026-117656)
- 31 Oct 2026, 15:25 UTC: First seen by agentprime
- 31 Oct 2026, 15:25 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/EEF-CVE-2026-117656)

## Sources

- [GitHub Advisory Database: GHSA-9fr5-g44g-9526](https://github.com/advisories/GHSA-9fr5-g44g-9526)
- [OSV: GHSA-9fr5-g44g-9526](https://osv.dev/vulnerability/GHSA-9fr5-g44g-9526)
- <https://github.com/pow-auth/assent/security/advisories/GHSA-9fr5-g44g-9526>
- <https://cna.erlef.org/cves/CVE-2026-117656.html>
- <https://github.com/pow-auth/assent/commit/a2d331e8c51376d6c0b04a81aad31e0b4d4d64a3>
- <https://github.com/pow-auth/assent/commit/18898bde0296152165ae470078490e5798329b1b>
- <https://hex.pm/packages/assent>

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-9fr5-g44g-9526>, 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-9fr5-g44g-9526/>. Everything for agents: <https://agentprime.io/llms.txt>.