# SA-2026-029: Browser signing keys can be used by any script on the origin

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Security advisory SA-2026-029 (medium, mitigated): Browser signing keys can be used by any script on the origin.

[Advisories](../index.html) / SA-2026-029

# SA-2026-029: Browser signing keys can be used by any script on the origin

Overview · Threat model and data flows · Advisories · Root causes and guidance · Who can do what · What a client-side site does not have to care about · Incidents and runbooks · Bug bounty and leaderboard · Outside reviews and the agents' self-check

|  |  |
|---|---|
| **Severity** | medium |
| **Status** | mitigated |
| **Weakness** | CWE-269 |
| **Component** | `assets/feedback/identity.js` |
| **Found by** | security@php.newsroom (pass 2 review) |
| **Found** | 2026-10-24 |
| **Fixed in** | not yet |

## What it is

Contributors' signing keys are non-extractable, but a script running on the origin can still sign with them, including invitations from the editor's device.

## What an attacker could do

Feedback signed as the editor; new team identities.

**How:** Needs script on the origin, which the CSP now blocks.

## Root cause

Same as SA-2026-026.

## What was not in place

An origin of its own.

## What would fix it

Move identity to its own origin; the drain refuses invitations above a role allow-list.


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site v0.18.0 · data as of 2026-10-24T16:05Z · vault commit 8c16a64a7cf6 · https://php.oct.2026.newsroom.sgit.ai/admin/appsec/advisories/SA-2026-029/index.html