Reject backslash in URL authority per RFC 3986#1659
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rodrigobnogueira wants to merge 4 commits intoaio-libs:masterfrom
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Reject backslash in URL authority per RFC 3986#1659rodrigobnogueira wants to merge 4 commits intoaio-libs:masterfrom
rodrigobnogueira wants to merge 4 commits intoaio-libs:masterfrom
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Backslashes are not valid in the authority component per RFC 3986. WHATWG parsers treat them as forward slashes, creating parsing inconsistencies that enable SSRF attacks when yarl is used alongside WHATWG-compliant parsers. Example SSRF vector: http://example.com\@evil.com - WHATWG preprocessor parses host=example.com (trusted) - yarl parses host=evil.com (attacker-controlled) because \ is kept in netloc and @ triggers userinfo splitting Fix: raise ValueError for any URL where the authority contains a backslash.
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Codecov Report✅ All modified and coverable lines are covered by tests. ❌ Your project check has failed because the head coverage (97.64%) is below the target coverage (100.00%). You can increase the head coverage or adjust the target coverage. Additional details and impacted files@@ Coverage Diff @@
## master #1659 +/- ##
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Coverage 99.47% 99.48%
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Lines 5942 5975 +33
Branches 283 285 +2
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What do these changes do?
Reject URLs whose authority (netloc) component contains a backslash (
\), which is not a valid character in the authority per RFC 3986. Previously, yarl silently accepted these URLs and treated the backslash as part of the host, producing unexpected parsed results.This aligns yarl's parsing with the RFC 3986 grammar where
\is not listed among valid authority characters (unreserved / pct-encoded / sub-delims / ":" / "@").Are there changes in behavior for the user?
Yes.
URL(r"http://example.com\path")now raisesValueErrorinstead of silently producing a misleading parsed result where the backslash becomes part of the host.Is it a substantial burden for the maintainers to support this?
No. It is a single guard in
split_url()in_parse.py, with four parametrized test cases.Related issue number
N/A
Checklist
CHANGES/folder