diff --git a/CHANGELOG.md b/CHANGELOG.md
index c8666a6..f271850 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -22,6 +22,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- Reject an under-indented or tab-indented continuation in a multi-line quoted
+  scalar. A quoted scalar's continuation must be indented past the parent block, so
+  `"a`\n`b"` (continuation in column 0) and `"bar`\n`\tbaz"` (tab indentation) are
+  malformed. The error is deferred until the closing quote is found, so an
+  unterminated quote still reports the missing quote (its root cause) rather than
+  the indentation symptom. Surpasses libyaml on QB6E and DK95/01, bringing
+  whole-suite conformance to 402/402.
 - Reject a tab used to indent flow-collection content. A tab is never indentation,
   so flow content reached through a tab below the continuation indent (`- [`\n
   `\tfoo`) is malformed, even though the tab inflates the column. A tab at or past
diff --git a/Sources/Parsing/LibYAML.Scanner.FlowScalar.swift b/Sources/Parsing/LibYAML.Scanner.FlowScalar.swift
index 992fb6c..d4f6f04 100644
--- a/Sources/Parsing/LibYAML.Scanner.FlowScalar.swift
+++ b/Sources/Parsing/LibYAML.Scanner.FlowScalar.swift
@@ -28,6 +28,11 @@ extension PureYAML.Parsing.LibYAML.Scanner {
         reader.skip()
         var state = FlowState()
         let quote: Unicode.Scalar = single ? "'" : "\""
+        let indent = indentEngine.indent + 1
+        // A continuation indented below `indent` is an error, but it is recorded
+        // and only raised once the quote is known to close; an unterminated quote
+        // reaches end of input first and reports that instead.
+        var indentError: PureYAML.Parsing.LibYAML.ScannerError?
         while true {
             if reader.column == 0, documentMarkerAhead() {
                 throw flowError("found unexpected document indicator", startMark)
@@ -39,10 +44,13 @@ extension PureYAML.Parsing.LibYAML.Scanner {
             if reader.peek() == quote {
                 break
             }
-            consumeFlowBreaks(&state)
+            consumeFlowBreaks(&state, indent: indent, quote: quote, startMark: startMark, error: &indentError)
             foldFlow(&state)
         }
         reader.skip()
+        if let indentError {
+            throw indentError
+        }
         return PureYAML.Parsing.LibYAML.Token(
             type: .scalar(value: state.string, style: single ? .singleQuoted : .doubleQuoted),
             startMark: startMark,
@@ -139,9 +147,18 @@ extension PureYAML.Parsing.LibYAML.Scanner {
 
     /// Consume blanks and line breaks between content, recording pending
     /// whitespace and folded breaks.
-    private mutating func consumeFlowBreaks(_ state: inout FlowState) {
+    private mutating func consumeFlowBreaks(
+        _ state: inout FlowState,
+        indent: Int,
+        quote: Unicode.Scalar,
+        startMark: PureYAML.Parsing.Mark,
+        error: inout PureYAML.Parsing.LibYAML.ScannerError?,
+    ) {
         while Classify.isBlank(reader.peek()) || Classify.isBreak(reader.peek()) {
             if Classify.isBlank(reader.peek()) {
+                if error == nil, state.leadingBlanks, reader.column < indent, Classify.isTab(reader.peek()), !blankLineAhead() {
+                    error = flowError("found a tab character that violates indentation", startMark)
+                }
                 if !state.leadingBlanks, let blank = reader.peek() {
                     state.whitespaces.unicodeScalars.append(blank)
                 }
@@ -156,6 +173,11 @@ extension PureYAML.Parsing.LibYAML.Scanner {
                 state.trailingBreaks += "\n"
             }
         }
+        // The continuation content must be indented at least `indent`; a less
+        // indented (non-closing, non-empty) line is malformed.
+        if error == nil, state.leadingBlanks, let next = reader.peek(), next != quote, !Classify.isBreakZ(next), reader.column < indent {
+            error = flowError("found wrong indentation in a multi-line quoted scalar", startMark)
+        }
     }
 
     /// Fold the pending breaks or whitespace into the value.
diff --git a/Tests/Fixtures/yaml-test-suite-manifest.yaml b/Tests/Fixtures/yaml-test-suite-manifest.yaml
index 4053908..aec0eda 100644
--- a/Tests/Fixtures/yaml-test-suite-manifest.yaml
+++ b/Tests/Fixtures/yaml-test-suite-manifest.yaml
@@ -10,8 +10,8 @@ source:
 # oracle:   json if in.json present, else none
 # status:   passing (PureYAML conformant today) | gap (not yet conformant)
 total: 402
-passing: 400
-gap: 2
+passing: 402
+gap: 0
 cases:
   - id: "229Q"
     name: "Spec Example 2.4. Sequence of Mappings"
@@ -1506,7 +1506,7 @@ cases:
     localPath: yaml-test-suite/DK95/01/in.yaml
     expected: reject
     oracle: json
-    status: gap
+    status: passing
     byteCount: 16
     lineCount: 2
   - id: "DK95/02"
@@ -2506,7 +2506,7 @@ cases:
     localPath: yaml-test-suite/QB6E/in.yaml
     expected: reject
     oracle: none
-    status: gap
+    status: passing
     byteCount: 20
     lineCount: 4
   - id: "QF4Y"