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ProbeLabs23 findings · 123 requirementsThe fastest JSON parser for Go — formally verified with ReqProof (real library, master).
Unescape lone-Unicode-surrogate mishandling synthesizes bogus non-BMP chars
This defect has been fixed and verified.
Introduced
When and where this issue first entered the codebase — the commit it traces back to, and the audit run that first flagged it.
Change history
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Severity, explained
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- risk area
- Data Integrity
Root cause
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escape.go:decodeUnicodeEscape (root cause at escape.go:126 in the pre-fix source) called decodeSingleUnicodeEscape(in[6:]) to read the low surrogate WITHOUT first verifying in[6:8] == "\u". Because decodeSingleUnicodeEscape assumes the "\u" prefix and reads hex at fixed offsets [2:6], any literal bytes following a lone high surrogate were misread as a low surrogate and a bogus non-BMP code point was synthesized. Additionally the lone-low-surrogate and high-then-non-low-surrogate cases returned a hard error instead of the U+FFFD substitution that encoding/json (and RFC 8259/WHATWG interoperability) use.
Disposition: Covered by a requirement
Proof it's fixed
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Blast radius
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Nothing to trace into
This finding links no requirements, so there is no dependency graph to follow. Everything we know about it is in the evidence above.
Discussions
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