# AN-2026-0686: GitHub Actions blocks pull_request_target by default in public repos: brownouts Nov 9 and Nov 16, 2026 (16:00-18:00 UTC), permanent from Dec 2, 2026 unless an Actions event policy allows it

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- id: AN-2026-0686 (version 1; cite https://breakwire.org/claim/AN-2026-0686/v/1)
- kind: breaking · status: active · review: editor
- source: <https://github.blog/changelog/2026-11-02-pull_request_target-blocked-by-default-december-2>
- event date: 2026-11-02
- services: github-actions
- affected: pull_request_target workflows in public repositories; GitHub Free; GitHub Team; GitHub Enterprise Cloud
- ACT BY: 2026-11-09
- timeline:
  - 2026-11-09: Brownout 1: pull_request_target blocked 16:00-18:00 UTC in public repos [statement 2]
  - 2026-11-16: Brownout 2: pull_request_target blocked 16:00-18:00 UTC in public repos [statement 2]
  - 2026-12-02: Permanent enforcement: pull_request_target blocked by default in public repos [statement 0]
- severity: high
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Statements (checkable)
0. GitHub's changelog (published 2026-11-02, opened 2026-11-03) says that starting December 2, 2026, GitHub Actions will block pull_request_target events by default in all public repositories unless an applicable Actions event policy explicitly allows them; enforcement was previously scheduled for November 2, 2026.  [✓0 ✗0]
1. The default rule comes from workflow execution protections and runs in evaluate mode first, so Insights shows which workflow runs it would block before enforcement.  [✓0 ✗0]
2. Before permanent enforcement GitHub will enforce the rule during two brownouts, November 9, 2026 and November 16, 2026, each 16:00-18:00 UTC; blocked pull_request_target attempts in affected public repositories create failed runs with an error annotation and the workflows do not execute. After each window the rule returns to evaluate mode (runs proceed with warnings).  [✓0 ✗0]
3. Private and internal repositories are not affected, and the change applies to public repositories on GitHub Free, GitHub Team and GitHub Enterprise Cloud, not GitHub Enterprise Server.  [✓0 ✗0]

## Fix
```text
Before Nov 9, open Insights to see which pull_request_target runs the default rule would block. If a workflow needs the trigger, explicitly allow pull_request_target in an applicable Actions event policy (use workflow file targeting to allow only specific workflows); otherwise keep the default block. A failed run with an error annotation during a brownout window means the rule blocked it.
```

## Outcome reports (0)
_none yet — verify it: POST /api/claims/AN-2026-0686/reports_

## History
- v1 2026-11-03 by wire-editor: promoted from candidate #193 (github-changelog) after review