diff --git a/pkg/routes/caldav/listStorageProvider.go b/pkg/routes/caldav/listStorageProvider.go
index ab0ccad31..5544d3ec7 100644
--- a/pkg/routes/caldav/listStorageProvider.go
+++ b/pkg/routes/caldav/listStorageProvider.go
@@ -175,16 +175,32 @@ func principalPathForUser(username string) string {
 // GetResourcesByList fetches a list of resources from a slice of paths
 func (vcls *VikunjaCaldavProjectStorage) GetResourcesByList(rpaths []string) (resources []data.Resource, err error) {
 
-	// Parse the set of resourcepaths into usable uids
-	// A path looks like this: /dav/projects/10/a6eb526d5748a5c499da202fe74f36ed1aea2aef.ics
-	// So we split the url in parts, take the last one and strip the ".ics" at the end
+	// Path format: /dav/projects/{projectID}/{uid}.ics.
+	// Remember the href's project ID per uid so the consistency check below
+	// can drop tasks requested via the wrong project (GHSA-48ch-p4gq-x46x).
 	var uids []string
+	uidURLProjects := map[string]int64{}
 	for _, path := range rpaths {
 		parts := strings.Split(path, "/")
 		if len(parts) < 5 {
 			continue
 		}
-		uids = append(uids, strings.TrimSuffix(parts[4], ".ics"))
+		// Skip malformed hrefs: without these guards an empty/non-numeric
+		// project would bypass the consistency check, and an empty UID
+		// would query for tasks with empty/NULL uids.
+		if !strings.HasSuffix(parts[4], ".ics") {
+			continue
+		}
+		uid := strings.TrimSuffix(parts[4], ".ics")
+		if uid == "" {
+			continue
+		}
+		urlProjectID, perr := strconv.ParseInt(parts[3], 10, 64)
+		if perr != nil {
+			continue
+		}
+		uids = append(uids, uid)
+		uidURLProjects[uid] = urlProjectID
 	}
 
 	if len(uids) == 0 {
@@ -207,6 +223,11 @@ func (vcls *VikunjaCaldavProjectStorage) GetResourcesByList(rpaths []string) (re
 	}
 
 	for _, t := range tasks {
+		// Closes the URL-path leak for calendar-multiget REPORTs
+		// (GHSA-48ch-p4gq-x46x).
+		if urlProjectID, ok := uidURLProjects[t.UID]; ok && urlProjectID != t.ProjectID {
+			continue
+		}
 		rr := VikunjaProjectResourceAdapter{
 			task: t,
 		}
diff --git a/pkg/routes/caldav/listStorageProvider_test.go b/pkg/routes/caldav/listStorageProvider_test.go
index caa92fec7..477b58e20 100644
--- a/pkg/routes/caldav/listStorageProvider_test.go
+++ b/pkg/routes/caldav/listStorageProvider_test.go
@@ -486,3 +486,50 @@ END:VCALENDAR`
 		assert.Equal(t, "uid-caldav-test-child-task-2", formerSiblingSubTask.UID)
 	})
 }
+
+// TestGetResourcesByList_URLProjectConsistency covers GHSA-48ch-p4gq-x46x.
+func TestGetResourcesByList_URLProjectConsistency(t *testing.T) {
+	u := &user.User{
+		ID:       15,
+		Username: "user15",
+	}
+
+	t.Run("drops task when href project does not match task project", func(t *testing.T) {
+		db.LoadAndAssertFixtures(t)
+
+		storage := &VikunjaCaldavProjectStorage{user: u}
+
+		// uid-caldav-test lives in project 36 (fixtures/tasks.yml id 40).
+		resources, err := storage.GetResourcesByList([]string{
+			"/dav/projects/38/uid-caldav-test.ics",
+		})
+		require.NoError(t, err)
+		assert.Empty(t, resources, "task must not be returned when href project mismatches")
+	})
+
+	t.Run("returns task when href project matches task project", func(t *testing.T) {
+		db.LoadAndAssertFixtures(t)
+
+		storage := &VikunjaCaldavProjectStorage{user: u}
+
+		resources, err := storage.GetResourcesByList([]string{
+			"/dav/projects/36/uid-caldav-test.ics",
+		})
+		require.NoError(t, err)
+		require.Len(t, resources, 1)
+	})
+
+	t.Run("drops task for unauthorized user", func(t *testing.T) {
+		db.LoadAndAssertFixtures(t)
+
+		// user 6 has no access to project 36
+		outsider := &user.User{ID: 6, Username: "user6"}
+		storage := &VikunjaCaldavProjectStorage{user: outsider}
+
+		resources, err := storage.GetResourcesByList([]string{
+			"/dav/projects/36/uid-caldav-test.ics",
+		})
+		require.NoError(t, err)
+		assert.Empty(t, resources, "unauthorized user must not receive any tasks")
+	})
+}
diff --git a/pkg/webtests/caldav_test.go b/pkg/webtests/caldav_test.go
index f338db71f..900772d0c 100644
--- a/pkg/webtests/caldav_test.go
+++ b/pkg/webtests/caldav_test.go
@@ -107,6 +107,42 @@ END:VCALENDAR`
 		assert.NotContains(t, rec.Body.String(), "Title Caldav Test")
 		assert.Equal(t, http.StatusNotFound, rec.Result().StatusCode)
 	})
+	t.Run("Multiget rejects UIDs from other projects", func(t *testing.T) {
+		e, _ := setupTestEnv()
+
+		// href claims project 38, but uid-caldav-test lives in project 36.
+		reportBody := `<?xml version="1.0" encoding="utf-8" ?>
+<C:calendar-multiget xmlns:D="DAV:" xmlns:C="urn:ietf:params:xml:ns:caldav">
+	<D:prop>
+		<D:getetag/>
+		<C:calendar-data/>
+	</D:prop>
+	<D:href>/dav/projects/38/uid-caldav-test.ics</D:href>
+</C:calendar-multiget>`
+
+		rec, err := newCaldavTestRequestWithUser(t, e, "REPORT", caldav.ProjectHandler, &testuser15, reportBody, nil, map[string]string{"project": "38"})
+		require.NoError(t, err)
+		assert.NotContains(t, rec.Body.String(), "Title Caldav Test")
+		assert.NotContains(t, rec.Body.String(), "Description Caldav Test")
+	})
+	t.Run("Multiget cross-user UID read is rejected", func(t *testing.T) {
+		e, _ := setupTestEnv()
+
+		reportBody := `<?xml version="1.0" encoding="utf-8" ?>
+<C:calendar-multiget xmlns:D="DAV:" xmlns:C="urn:ietf:params:xml:ns:caldav">
+	<D:prop>
+		<D:getetag/>
+		<C:calendar-data/>
+	</D:prop>
+	<D:href>/dav/projects/36/uid-caldav-test.ics</D:href>
+</C:calendar-multiget>`
+
+		// testuser6 cannot access project 36 where uid-caldav-test lives.
+		rec, err := newCaldavTestRequestWithUser(t, e, "REPORT", caldav.ProjectHandler, &testuser6, reportBody, nil, map[string]string{"project": "36"})
+		require.NoError(t, err)
+		assert.NotContains(t, rec.Body.String(), "Title Caldav Test")
+		assert.NotContains(t, rec.Body.String(), "Description Caldav Test")
+	})
 }
 
 func TestCaldavDiscovery(t *testing.T) {