diff --git a/compiler/rustc_session/src/options.rs b/compiler/rustc_session/src/options.rs
index 6ae0d9721bc00..88c38aa047b1d 100644
--- a/compiler/rustc_session/src/options.rs
+++ b/compiler/rustc_session/src/options.rs
@@ -726,7 +726,29 @@ fn build_options<O: Default>(
                 }
                 if let Some(tmod) = *tmod {
                     let v = value.map_or(String::new(), ToOwned::to_owned);
-                    collected_options.target_modifiers.insert(tmod, v);
+
+                    // Accumulate all the -Zsanitizer flags into a single target modifier.
+                    match tmod {
+                        OptionsTargetModifiers::UnstableOptions(
+                            UnstableOptionsTargetModifiers::Sanitizer,
+                        ) => {
+                            collected_options
+                                .target_modifiers
+                                .entry(tmod)
+                                .and_modify(|existing| {
+                                    if !existing.is_empty() && !v.is_empty() {
+                                        existing.push(',');
+                                        existing.push_str(&v);
+                                    } else if existing.is_empty() {
+                                        *existing = v.clone();
+                                    }
+                                })
+                                .or_insert(v);
+                        }
+                        _ => {
+                            collected_options.target_modifiers.insert(tmod, v);
+                        }
+                    }
                 }
                 if let Some(mitigation) = mitigation {
                     collected_options.mitigations.reset_mitigation(*mitigation, index);
diff --git a/tests/codegen-llvm/sanitizer/multiple-sanitizers.rs b/tests/codegen-llvm/sanitizer/multiple-sanitizers.rs
new file mode 100644
index 0000000000000..f320a1673d2e9
--- /dev/null
+++ b/tests/codegen-llvm/sanitizer/multiple-sanitizers.rs
@@ -0,0 +1,16 @@
+// Verifies that multiple compatible sanitizers (CFI + SafeStack) can be enabled together
+// and their target modifiers accumulate instead of overwriting.
+//
+//@ only-x86_64
+//@ only-linux
+//@ compile-flags: -Zsanitizer=cfi -Zsanitizer=safestack -Clto -Ccodegen-units=1 -C unsafe-allow-abi-mismatch=sanitizer
+
+#![crate_type = "lib"]
+
+// CHECK: ; Function Attrs:{{.*}}safestack
+// CHECK: define{{.*}}foo{{.*}}!type
+pub fn foo(f: fn(i32) -> i32, arg: i32) -> i32 {
+    f(arg)
+}
+
+// CHECK: attributes #0 = {{.*}}safestack{{.*}}