diff --git a/net-im/libsignal/files/patch-rust_bridge_shared_types_src_ffi_mod.rs b/net-im/libsignal/files/patch-rust_bridge_shared_types_src_ffi_mod.rs
new file mode 100644
index 000000000000..a9213fbb60b6
--- /dev/null
+++ b/net-im/libsignal/files/patch-rust_bridge_shared_types_src_ffi_mod.rs
@@ -0,0 +1,27 @@
+--- rust/bridge/shared/types/src/ffi/mod.rs.orig	2026-06-25 20:33:59 UTC
++++ rust/bridge/shared/types/src/ffi/mod.rs
+@@ -79,8 +79,7 @@ impl<T> BorrowedMutableSliceOf<T> {
+     }
+ }
+ 
+-/// A buffer of `length` elements of type `T`, allocated with the alignment of
+-/// [`libc::max_align_t`].
++/// A buffer of `length` elements of type `T`, allocated with a fixed alignment.
+ ///
+ /// The number of bytes allocated is stored in `size_bytes`.
+ ///
+@@ -100,8 +99,13 @@ impl<T> OwnedBufferOfMaxAligned<T> {
+ }
+ 
+ impl<T> OwnedBufferOfMaxAligned<T> {
+-    pub const ALIGNMENT: usize = std::mem::align_of::<libc::max_align_t>();
++    // A reasonable max alignment for most types we use. (We aren't using SIMD types here.)
++    // A const-time assertion will trip if this alignment isn't sufficient.
++    pub const ALIGNMENT: usize = 16;
+     pub fn layout_for_count(count: usize) -> std::alloc::Layout {
++        const {
++            assert!(std::mem::align_of::<T>() <= Self::ALIGNMENT);
++        }
+         std::alloc::Layout::array::<T>(count)
+             .expect("valid layout")
+             .align_to(Self::ALIGNMENT)