diff --git a/CHANGELOG.md b/CHANGELOG.md
index 75d4cf1..eaf8ca9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@
 - Advisories distinguish the `affected_symbols` a fix changed from the public `entry_points` through which they are reached, each justified and carrying `conditions` (checkable argument values, or `semantic` ones kept as pending review); `modules` names what the package installs. Every dependency finding records its evidence `level`: `declared`, `imported`, `reachable` or `exploitable`.
 - A call to an API affected by several advisories of the pinned release reports every one of them, not the first listed.
 - One advisory per identifier and package: a later contributor replaces an earlier one, so a curated feed refines the bundled sample, and the sample names the modules its packages install.
+- A version specifier may be a union of ranges separated by `||`, as an advisory over several release series needs (`>=4.2,<4.2.28 || >=5.2,<5.2.11`); the OSV import produces one such advisory per package instead of one per range.
 
 ### Plugins
 
diff --git a/docs/usage.md b/docs/usage.md
index bc3d235..68cef3f 100644
--- a/docs/usage.md
+++ b/docs/usage.md
@@ -241,7 +241,8 @@ coretrace-python-analyzer --check src/ --advisories advisories.json
 
 A directory check reads `advisories.json` at the project root and every file passed
 with `--advisories`; a local entry wins over a plugin's for the same advisory. The file
-lists advisories with the package, the vulnerable version range and, optionally, the
+lists advisories with the package, the vulnerable version range (a specifier, or several
+separated by `||` when several release series are affected) and, optionally, the
 affected APIs that feed reachability and correlation:
 
 ```json
diff --git a/src/coretrace_python/dependency/advisories.py b/src/coretrace_python/dependency/advisories.py
index ebd39d9..676558f 100644
--- a/src/coretrace_python/dependency/advisories.py
+++ b/src/coretrace_python/dependency/advisories.py
@@ -84,8 +84,9 @@ def import_osv(records: Iterable[Mapping[str, Any]]) -> tuple[Advisory, ...]:
             if str(package.get("ecosystem", "")).lower() != "pypi" or not package.get("name"):
                 continue
             name = normalize(str(package["name"]))
-            for specifier in _specifiers(affected.get("ranges") or []):
-                advisories.append(Advisory(identifier, name, specifier, summary, severity, (), aliases))
+            specifiers = _specifiers(affected.get("ranges") or [])
+            if specifiers:
+                advisories.append(Advisory(identifier, name, " || ".join(specifiers), summary, severity, (), aliases))
     return tuple(advisories)
 
 
diff --git a/src/coretrace_python/dependency/graph.py b/src/coretrace_python/dependency/graph.py
index 4c41f7a..52f97fc 100644
--- a/src/coretrace_python/dependency/graph.py
+++ b/src/coretrace_python/dependency/graph.py
@@ -50,6 +50,13 @@ def padded(self, length: int) -> tuple[int, ...]:
         return self.parts + (0,) * (length - len(self.parts))
 
     def satisfies(self, specifier: str) -> bool:
+        """Whether this version is in ``specifier``: comma-separated clauses all hold, and
+        ``||`` separates alternatives, as an advisory over several release series needs
+        (``>=4.2,<4.2.28 || >=5.2,<5.2.11``)."""
+
+        return any(self._satisfies_all(alternative) for alternative in _alternatives(specifier))
+
+    def _satisfies_all(self, specifier: str) -> bool:
         for clause in [c.strip() for c in specifier.split(",") if c.strip()]:
             match = _CLAUSE.match(clause)
             if match is None:
@@ -91,12 +98,17 @@ def _satisfies_clause(self, operator: str, wanted: Version, raw: str) -> bool:
         return True
 
 
+def _alternatives(specifier: str) -> list[str]:
+    return [a for a in specifier.split("||") if a.strip()] or [""]
+
+
 def _lower_bounds(specifier: str) -> list[Version]:
     bounds: list[Version] = []
-    for clause in [c.strip() for c in specifier.split(",") if c.strip()]:
-        match = _CLAUSE.match(clause)
-        if match is not None and match.group(1) in (">=", ">", "~=", "^", "==", "==="):
-            bounds.append(Version.parse(match.group(2)))
+    for alternative in _alternatives(specifier):
+        for clause in [c.strip() for c in alternative.split(",") if c.strip()]:
+            match = _CLAUSE.match(clause)
+            if match is not None and match.group(1) in (">=", ">", "~=", "^", "==", "==="):
+                bounds.append(Version.parse(match.group(2)))
     return bounds
 
 
diff --git a/tests/test_advisory_feeds.py b/tests/test_advisory_feeds.py
index 490014a..c05a338 100644
--- a/tests/test_advisory_feeds.py
+++ b/tests/test_advisory_feeds.py
@@ -124,10 +124,11 @@ def test_osv_severity_summary_and_ecosystem_handling() -> None:
         ("GHSA-6", Severity.MEDIUM),
         ("GHSA-7", Severity.MEDIUM),
         ("GHSA-9", Severity.MEDIUM),
-        ("GHSA-9", Severity.MEDIUM),
     ]
     assert advisories[2].summary == "Long details."
-    assert [a.vulnerable for a in advisories if a.id == "GHSA-9"] == ["<1.1", ">=2.0,<2.1"]
+    # Several ranges of one package are one advisory over a union of ranges: advisories
+    # are merged by identifier, so two records would keep only the last series.
+    assert [a.vulnerable for a in advisories if a.id == "GHSA-9"] == ["<1.1 || >=2.0,<2.1"]
 
 
 def test_osv_dumps_are_read_from_files_directories_and_archives(tmp_path: Path) -> None:
diff --git a/tests/test_dependencies.py b/tests/test_dependencies.py
index 0a56808..fe70a29 100644
--- a/tests/test_dependencies.py
+++ b/tests/test_dependencies.py
@@ -163,6 +163,11 @@ def test_graphs_merge_and_locks_pin_declared_requirements() -> None:
         ("1.26.4", ">=1.26.5", False),
         ("2.11.0", "^2.11", True),
         ("3.0.0", "^2.11", False),
+        # An advisory over several release series is a union of ranges.
+        ("4.2.27", ">=4.2,<4.2.28 || >=5.2,<5.2.11", True),
+        ("5.2.10", ">=4.2,<4.2.28 || >=5.2,<5.2.11", True),
+        ("5.0.0", ">=4.2,<4.2.28 || >=5.2,<5.2.11", False),
+        ("5.2.11", ">=4.2,<4.2.28 || >=5.2,<5.2.11", False),
     ],
 )
 def test_version_matching(version: str, specifier: str, expected: bool) -> None:
@@ -182,6 +187,13 @@ def test_requirements_may_allow_a_vulnerable_version() -> None:
     assert unspecified.may_match("<5.4") is True
 
 
+def test_an_unpinned_requirement_may_match_any_series_of_a_union() -> None:
+    union = ">=4.2,<4.2.28 || >=5.2,<5.2.11"
+    assert Requirement.parse("django>=5.2", SourceId("r.txt"), 1).may_match(union) is True
+    assert Requirement.parse("django>=5.0,<5.1", SourceId("r.txt"), 1).may_match(union) is False
+    assert Requirement.parse("django==5.2.10", SourceId("r.txt"), 1).may_match(union) is True
+
+
 # --------------------------------------------------------------------------- engine