diff --git a/.github/workflows/wai-quantum-sme.yml b/.github/workflows/wai-quantum-sme.yml
index 4f49399dd..aaf1cdbe7 100644
--- a/.github/workflows/wai-quantum-sme.yml
+++ b/.github/workflows/wai-quantum-sme.yml
@@ -5,9 +5,10 @@ name: wai-quantum matrix-extension member
 # against the CPU reference's pinned corpus digests.
 #
 # - sme-emulated (the container runner): the member's device tests for aarch64
-#   Linux, run through the host's user-mode emulator (its binfmt handler, which
-#   emulates SME); the runner declares the emulator, and every certificate says
-#   it was earned there, never on silicon.
+#   Linux, run under a user-mode emulator the job fetches and runs itself
+#   (Debian's static QEMU, pinned, which emulates SME), never the host's binfmt
+#   handler; the job declares the emulator, and every certificate says it was
+#   earned there, never on silicon.
 # - sme-absent (the macOS runner, whose processor has no SME): the same build
 #   finds no member and says why.
 #
@@ -62,12 +63,17 @@ jobs:
       options: --memory=6g --memory-swap=6g
     env:
       WAI_QUANTUM_SME_EXPECT: cpu-matrix-sme
-      # The host's binfmt handler runs every aarch64 binary; its emulator is
-      # what the certificates name.
-      WAI_QUANTUM_SME_EMULATOR: qemu-user 8.2.2 (the host's binfmt handler)
-      # Run the test binary directly, so the host's handler (which emulates
-      # SME) runs it, not the image's older emulator.
-      CARGO_TARGET_AARCH64_UNKNOWN_LINUX_GNU_RUNNER: env
+      # The emulator every aarch64 test binary runs under, which the certificates
+      # name: Debian's static QEMU, SHA-256 pinned, fetched by the job and named as
+      # cargo's runner. Not the image's own (5.1), and not the host's binfmt
+      # handler, which some `linux` runners lack and others run at another
+      # version. (Not QEMU_*: qemu-user reads every QEMU_<option> variable as that
+      # option.)
+      WAI_QUANTUM_SME_EMULATOR: qemu-user 10.0.13 (Debian's static build, run by the job)
+      USER_EMULATOR_VERSION: 10.0.13
+      USER_EMULATOR_DEB: qemu-user_10.0.13+ds-0+deb13u1_amd64.deb
+      USER_EMULATOR_SHA256: ca6ede739327a20ae5a3498230c8a3a9a072c586e131bc6bcc1201eb1725e336
+      USER_EMULATOR_SHA1: dec1373851d29f91642c197f4a339d0d2ad25ed0
     steps:
       # The image has no Node for a checkout action: the forge's archive of the
       # exact commit, its embedded commit id checked.
@@ -99,6 +105,33 @@ jobs:
           fi
           rustup toolchain install
           rustup target add aarch64-unknown-linux-gnu
+          # The emulator, fetched once per host into the cache (under the lock above)
+          # and checked against its pin, then named as cargo's runner, so this leg
+          # passes or fails the same on every `linux` runner.
+          q="$cache/qemu-user-$USER_EMULATOR_VERSION"
+          if [ ! -x "$q/qemu-aarch64" ]; then
+            d="$cache/qemu-user-fetch"; rm -rf "$d" && mkdir "$d"
+            curl -sSfL -o "$d/$USER_EMULATOR_DEB" "https://deb.debian.org/debian/pool/main/q/qemu/$USER_EMULATOR_DEB" \
+              || curl -sSfL -o "$d/$USER_EMULATOR_DEB" "https://snapshot.debian.org/file/$USER_EMULATOR_SHA1"
+            echo "$USER_EMULATOR_SHA256  $d/$USER_EMULATOR_DEB" | sha256sum -c -
+            dpkg-deb --fsys-tarfile "$d/$USER_EMULATOR_DEB" | tar -x -C "$d" ./usr/bin/qemu-aarch64
+            rm -rf "$q.tmp" && mkdir "$q.tmp" && mv "$d/usr/bin/qemu-aarch64" "$q.tmp/"
+            rm -rf "$q" && mv "$q.tmp" "$q" && rm -rf "$d"
+          fi
+          runner="$q/qemu-aarch64 -L /usr/aarch64-linux-gnu"
+          export CARGO_TARGET_AARCH64_UNKNOWN_LINUX_GNU_RUNNER="$runner"
+          # Preflight: a trivial program, built for the target and run as cargo will run
+          # the tests. An emulator that cannot run it fails the leg here, saying so,
+          # rather than as a test that never ran.
+          cat > "$RUNNER_TEMP/probe.c" <<'EOF'
+          #include <stdio.h>
+          #include <sys/utsname.h>
+          int main(void) { struct utsname u; if (uname(&u) != 0) return 1; printf("%s\n", u.machine); return 0; }
+          EOF
+          aarch64-linux-gnu-gcc -o "$RUNNER_TEMP/probe" "$RUNNER_TEMP/probe.c"
+          got="$($runner "$RUNNER_TEMP/probe")" || { echo "::error::the emulator cannot run an aarch64 program: $runner"; exit 1; }
+          [ "$got" = aarch64 ] || { echo "::error::the preflight program ran as $got, not aarch64"; exit 1; }
+          echo "emulator: $("$q/qemu-aarch64" --version | head -1); an aarch64 program runs under it"
           report="$(mktemp)"
           WAI_QUANTUM_SME_REPORT="$report" cargo test --locked --release -j 6 --target aarch64-unknown-linux-gnu --features quantum_fabric_sme --test sme_member -- --test-threads=1 2>&1 | tee "$cache/device.log"
           grep -qE '^test result: ok\. 9 passed; 0 failed' "$cache/device.log" || { echo "::error::not every device test ran and passed"; exit 1; }
diff --git a/.github/workflows/wai-quantum-vector.yml b/.github/workflows/wai-quantum-vector.yml
index 268560eb3..83669449e 100644
--- a/.github/workflows/wai-quantum-vector.yml
+++ b/.github/workflows/wai-quantum-vector.yml
@@ -10,7 +10,8 @@ name: wai-quantum CPU vector units
 #   checks the avx2 member as on any other;
 # - avx2 and avx512 on silicon together: framework-128gb's processor, which has
 #   both, one member each;
-# - sve and rvv under the host's user-mode emulator (its binfmt handler), at
+# - sve and rvv under a user-mode emulator the job fetches and runs itself
+#   (Debian's static QEMU, pinned), never the host's binfmt handler, at
 #   several vector lengths each: the scalable kernels set their length per
 #   pass, and every leg checks the length the member read from the unit is the
 #   one the emulator was given, so a leg cannot pass at the wrong length;
@@ -74,41 +75,47 @@ jobs:
             key: cpu-vector-avx2
             bits: 256
             emulator: ''
+            qemu: ''
             qemu_cpu: ''
           - name: sve 128-bit (aarch64, emulated)
             target: aarch64-unknown-linux-gnu
             image: ghcr.io/cross-rs/aarch64-unknown-linux-gnu@sha256:7f8308a8734d9fcd2ebbe9a3e4bdea74af293f0799d80c3cc341e340cda49a4c
             key: cpu-vector-sve
             bits: 128
-            emulator: qemu-user 8.2.2 (the host's binfmt handler)
+            emulator: qemu-user 10.0.13 (Debian's static build, run by the job)
+            qemu: aarch64
             qemu_cpu: max,sve-default-vector-length=16
           - name: sve 512-bit (aarch64, emulated)
             target: aarch64-unknown-linux-gnu
             image: ghcr.io/cross-rs/aarch64-unknown-linux-gnu@sha256:7f8308a8734d9fcd2ebbe9a3e4bdea74af293f0799d80c3cc341e340cda49a4c
             key: cpu-vector-sve
             bits: 512
-            emulator: qemu-user 8.2.2 (the host's binfmt handler)
+            emulator: qemu-user 10.0.13 (Debian's static build, run by the job)
+            qemu: aarch64
             qemu_cpu: max,sve-default-vector-length=64
           - name: sve 2048-bit (aarch64, emulated)
             target: aarch64-unknown-linux-gnu
             image: ghcr.io/cross-rs/aarch64-unknown-linux-gnu@sha256:7f8308a8734d9fcd2ebbe9a3e4bdea74af293f0799d80c3cc341e340cda49a4c
             key: cpu-vector-sve
             bits: 2048
-            emulator: qemu-user 8.2.2 (the host's binfmt handler)
+            emulator: qemu-user 10.0.13 (Debian's static build, run by the job)
+            qemu: aarch64
             qemu_cpu: max,sve-default-vector-length=256
           - name: rvv 128-bit (riscv64, emulated)
             target: riscv64gc-unknown-linux-gnu
             image: ghcr.io/cross-rs/riscv64gc-unknown-linux-gnu@sha256:67ee97dd4719390d299edfcf39f226360ccfb1539e08b078ec187d4848415794
             key: cpu-vector-rvv
             bits: 128
-            emulator: qemu-user 8.2.2 (the host's binfmt handler)
+            emulator: qemu-user 10.0.13 (Debian's static build, run by the job)
+            qemu: riscv64
             qemu_cpu: rv64,v=true,vlen=128,elen=64
           - name: rvv 1024-bit (riscv64, emulated)
             target: riscv64gc-unknown-linux-gnu
             image: ghcr.io/cross-rs/riscv64gc-unknown-linux-gnu@sha256:67ee97dd4719390d299edfcf39f226360ccfb1539e08b078ec187d4848415794
             key: cpu-vector-rvv
             bits: 1024
-            emulator: qemu-user 8.2.2 (the host's binfmt handler)
+            emulator: qemu-user 10.0.13 (Debian's static build, run by the job)
+            qemu: riscv64
             qemu_cpu: rv64,v=true,vlen=1024,elen=64
     container:
       image: ${{ matrix.image }}
@@ -116,10 +123,16 @@ jobs:
     env:
       WAI_QUANTUM_VECTOR_EXPECT: ${{ matrix.key }}
       WAI_QUANTUM_VECTOR_EMULATOR: ${{ matrix.emulator }}
-      # Run test binaries directly, so the host's handler runs them with the
-      # processor given here, not the image's older emulator.
-      CARGO_TARGET_AARCH64_UNKNOWN_LINUX_GNU_RUNNER: env
-      CARGO_TARGET_RISCV64GC_UNKNOWN_LINUX_GNU_RUNNER: env
+      # The emulator every foreign test binary runs under: Debian's static QEMU,
+      # SHA-256 pinned, fetched by the job and named as cargo's runner. Not the
+      # image's own (5.1 for aarch64, 6.1 for riscv64), and not the host's binfmt
+      # handler, which some `linux` runners lack and others run at another
+      # version. (Not QEMU_*: qemu-user reads every QEMU_<option> variable as that
+      # option.)
+      USER_EMULATOR_VERSION: 10.0.13
+      USER_EMULATOR_DEB: qemu-user_10.0.13+ds-0+deb13u1_amd64.deb
+      USER_EMULATOR_SHA256: ca6ede739327a20ae5a3498230c8a3a9a072c586e131bc6bcc1201eb1725e336
+      USER_EMULATOR_SHA1: dec1373851d29f91642c197f4a339d0d2ad25ed0
     steps:
       # The image has no Node for a checkout action: the forge's archive of the
       # exact commit, its embedded commit id checked.
@@ -153,6 +166,36 @@ jobs:
           rustup target add ${{ matrix.target }}
           # The emulated processor, for the test binaries only.
           if [ -n "${{ matrix.qemu_cpu }}" ]; then export QEMU_CPU="${{ matrix.qemu_cpu }}"; fi
+          # A trivial program for the preflight below: it prints the machine it runs on.
+          cat > "$RUNNER_TEMP/probe.c" <<'EOF'
+          #include <stdio.h>
+          #include <sys/utsname.h>
+          int main(void) { struct utsname u; if (uname(&u) != 0) return 1; printf("%s\n", u.machine); return 0; }
+          EOF
+          if [ -n "${{ matrix.qemu }}" ]; then
+            # The emulator, fetched once per host into the cache (under the lock above)
+            # and checked against its pin, then named as cargo's runner, so this leg
+            # passes or fails the same on every `linux` runner.
+            q="$cache/qemu-user-$USER_EMULATOR_VERSION"
+            if [ ! -x "$q/qemu-aarch64" ] || [ ! -x "$q/qemu-riscv64" ]; then
+              d="$cache/qemu-user-fetch"; rm -rf "$d" && mkdir "$d"
+              curl -sSfL -o "$d/$USER_EMULATOR_DEB" "https://deb.debian.org/debian/pool/main/q/qemu/$USER_EMULATOR_DEB" \
+                || curl -sSfL -o "$d/$USER_EMULATOR_DEB" "https://snapshot.debian.org/file/$USER_EMULATOR_SHA1"
+              echo "$USER_EMULATOR_SHA256  $d/$USER_EMULATOR_DEB" | sha256sum -c -
+              dpkg-deb --fsys-tarfile "$d/$USER_EMULATOR_DEB" | tar -x -C "$d" ./usr/bin/qemu-aarch64 ./usr/bin/qemu-riscv64
+              rm -rf "$q.tmp" && mkdir "$q.tmp" && mv "$d/usr/bin/qemu-aarch64" "$d/usr/bin/qemu-riscv64" "$q.tmp/"
+              rm -rf "$q" && mv "$q.tmp" "$q" && rm -rf "$d"
+            fi
+            runner="$q/qemu-${{ matrix.qemu }} -L /usr/${{ matrix.qemu }}-linux-gnu"
+            export "CARGO_TARGET_$(printf %s "${{ matrix.target }}" | tr 'a-z-' 'A-Z_')_RUNNER=$runner"
+            # Preflight: the trivial program, built for the target and run as cargo will
+            # run the tests. An emulator that cannot run it fails the leg here, saying
+            # so, rather than as a test that never ran.
+            "${{ matrix.qemu }}-linux-gnu-gcc" -o "$RUNNER_TEMP/probe" "$RUNNER_TEMP/probe.c"
+            got="$($runner "$RUNNER_TEMP/probe")" || { echo "::error::the emulator cannot run a program for ${{ matrix.target }}: $runner"; exit 1; }
+            [ "$got" = "${{ matrix.qemu }}" ] || { echo "::error::the preflight program ran as $got, not ${{ matrix.qemu }}"; exit 1; }
+            echo "emulator: $("$q/qemu-${{ matrix.qemu }}" --version | head -1), cpu ${QEMU_CPU:-default}; a program for ${{ matrix.target }} runs under it"
+          fi
           # Every unit this processor has must be declared, so on silicon the
           # declaration comes from the kernel's own flags, not the probe under test.
           if [ "${{ matrix.key }}" = cpu-vector-avx2 ] && grep -qw avx512f /proc/cpuinfo; then