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fix: block mixed-case denylist bypass in setup-python-env action #86

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fix: block mixed-case denylist bypass in setup-python-env action #86

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Copilot Feb 19, 2026
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fix: lowercase token before denylist comparison to block mixed-case f…
Copilot Feb 19, 2026
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4 changes: 3 additions & 1 deletion .github/actions/setup-python-env/action.yml
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Original file line number Diff line number Diff line change
Expand Up @@ -39,7 +39,9 @@ runs:
# NOTE: '--' (end-of-options marker) is intentionally allowed; positional args would fail validation.
for arg in $EXTRA_ARGS; do
# Denylist: block flags that could redirect dependency resolution to an attacker-controlled index.
if [[ "$arg" =~ ^--(index-url|extra-index-url|trusted-host|find-links)(=|$) ]]; then
# Lowercase the token before comparison so mixed-case variants (e.g. --Index-Url) are also blocked.
arg_lower="${arg,,}"
if [[ "$arg_lower" =~ ^--(index-url|extra-index-url|trusted-host|find-links)(=|$) ]]; then
echo "::error::Blocked dangerous extra-args token: '$arg'. Registry overrides are not permitted." >&2
exit 1
fi
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