diff --git a/ci/docker/aarch64-linux-android/Dockerfile b/ci/docker/aarch64-linux-android/Dockerfile
index 0e5baf0854238..91c074150f94d 100644
--- a/ci/docker/aarch64-linux-android/Dockerfile
+++ b/ci/docker/aarch64-linux-android/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:25.04
+FROM ubuntu:26.04
 
 RUN dpkg --add-architecture i386
 RUN apt-get update && apt-get install -y --no-install-recommends \
diff --git a/ci/docker/aarch64-unknown-linux-gnu/Dockerfile b/ci/docker/aarch64-unknown-linux-gnu/Dockerfile
index e6b1798b1cfbf..e734c9c127b68 100644
--- a/ci/docker/aarch64-unknown-linux-gnu/Dockerfile
+++ b/ci/docker/aarch64-unknown-linux-gnu/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:25.04
+FROM ubuntu:26.04
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
     ca-certificates \
diff --git a/ci/docker/aarch64-unknown-linux-musl/Dockerfile b/ci/docker/aarch64-unknown-linux-musl/Dockerfile
index 15c38af65ce92..4173a97435e5f 100644
--- a/ci/docker/aarch64-unknown-linux-musl/Dockerfile
+++ b/ci/docker/aarch64-unknown-linux-musl/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:25.04
+FROM ubuntu:26.04
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
     ca-certificates \
diff --git a/ci/docker/arm-linux-androideabi/Dockerfile b/ci/docker/arm-linux-androideabi/Dockerfile
index 23afe49970e71..657ff81097c7e 100644
--- a/ci/docker/arm-linux-androideabi/Dockerfile
+++ b/ci/docker/arm-linux-androideabi/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:25.04
+FROM ubuntu:26.04
 
 RUN dpkg --add-architecture i386
 RUN apt-get update && apt-get install -y --no-install-recommends \
diff --git a/ci/docker/asmjs-unknown-emscripten/Dockerfile b/ci/docker/asmjs-unknown-emscripten/Dockerfile
index 312eca1146dba..5663e29df51f7 100644
--- a/ci/docker/asmjs-unknown-emscripten/Dockerfile
+++ b/ci/docker/asmjs-unknown-emscripten/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:25.04
+FROM ubuntu:26.04
 
 # This is a workaround to avoid the interaction with tzdata.
 ENV DEBIAN_FRONTEND=noninteractive
diff --git a/ci/docker/i686-linux-android/Dockerfile b/ci/docker/i686-linux-android/Dockerfile
index 96507d7fc2275..450df8b3c8105 100644
--- a/ci/docker/i686-linux-android/Dockerfile
+++ b/ci/docker/i686-linux-android/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:25.04
+FROM ubuntu:26.04
 
 RUN dpkg --add-architecture i386
 RUN apt-get update && apt-get install -y --no-install-recommends \
diff --git a/ci/docker/i686-unknown-linux-gnu/Dockerfile b/ci/docker/i686-unknown-linux-gnu/Dockerfile
index b1596071b8f63..cb2d4e7d42e1d 100644
--- a/ci/docker/i686-unknown-linux-gnu/Dockerfile
+++ b/ci/docker/i686-unknown-linux-gnu/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:25.04
+FROM ubuntu:26.04
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
         ca-certificates \
diff --git a/ci/docker/i686-unknown-linux-musl/Dockerfile b/ci/docker/i686-unknown-linux-musl/Dockerfile
index 225823d6143c5..b1926457a150a 100644
--- a/ci/docker/i686-unknown-linux-musl/Dockerfile
+++ b/ci/docker/i686-unknown-linux-musl/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:25.04
+FROM ubuntu:26.04
 
 RUN dpkg --add-architecture i386 && \
     apt-get update && apt-get install -y --no-install-recommends \
diff --git a/ci/docker/loongarch64-unknown-linux-gnu/Dockerfile b/ci/docker/loongarch64-unknown-linux-gnu/Dockerfile
index ab13f33f1187d..10d706bcb1c18 100644
--- a/ci/docker/loongarch64-unknown-linux-gnu/Dockerfile
+++ b/ci/docker/loongarch64-unknown-linux-gnu/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:25.04
+FROM ubuntu:26.04
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
     ca-certificates \
diff --git a/ci/docker/loongarch64-unknown-linux-musl/Dockerfile b/ci/docker/loongarch64-unknown-linux-musl/Dockerfile
index c3066e027a40d..7944dd0c8d73b 100644
--- a/ci/docker/loongarch64-unknown-linux-musl/Dockerfile
+++ b/ci/docker/loongarch64-unknown-linux-musl/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:25.04
+FROM ubuntu:26.04
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
     ca-certificates \
diff --git a/ci/docker/powerpc64-unknown-linux-gnu/Dockerfile b/ci/docker/powerpc64-unknown-linux-gnu/Dockerfile
index f7907a32347ac..369916bb6771a 100644
--- a/ci/docker/powerpc64-unknown-linux-gnu/Dockerfile
+++ b/ci/docker/powerpc64-unknown-linux-gnu/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:25.04
+FROM ubuntu:26.04
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
     ca-certificates \
diff --git a/ci/docker/powerpc64le-unknown-linux-gnu/Dockerfile b/ci/docker/powerpc64le-unknown-linux-gnu/Dockerfile
index f2f0a6e20c7b2..98dc2c44df03b 100644
--- a/ci/docker/powerpc64le-unknown-linux-gnu/Dockerfile
+++ b/ci/docker/powerpc64le-unknown-linux-gnu/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:25.04
+FROM ubuntu:26.04
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
     ca-certificates \
diff --git a/ci/docker/powerpc64le-unknown-linux-musl/Dockerfile b/ci/docker/powerpc64le-unknown-linux-musl/Dockerfile
index 10cd93981a181..574cdd90bbef6 100644
--- a/ci/docker/powerpc64le-unknown-linux-musl/Dockerfile
+++ b/ci/docker/powerpc64le-unknown-linux-musl/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:25.04
+FROM ubuntu:26.04
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
     ca-certificates \
diff --git a/ci/docker/riscv64gc-unknown-linux-gnu/Dockerfile b/ci/docker/riscv64gc-unknown-linux-gnu/Dockerfile
index 10395b72406b0..3ea528a57ec78 100644
--- a/ci/docker/riscv64gc-unknown-linux-gnu/Dockerfile
+++ b/ci/docker/riscv64gc-unknown-linux-gnu/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:25.04
+FROM ubuntu:26.04
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
     ca-certificates \
diff --git a/ci/docker/s390x-unknown-linux-gnu/Dockerfile b/ci/docker/s390x-unknown-linux-gnu/Dockerfile
index 4e0e3e7d514f9..47f2cd76fc055 100644
--- a/ci/docker/s390x-unknown-linux-gnu/Dockerfile
+++ b/ci/docker/s390x-unknown-linux-gnu/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:25.04
+FROM ubuntu:26.04
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
     ca-certificates \
diff --git a/ci/docker/s390x-unknown-linux-musl/Dockerfile b/ci/docker/s390x-unknown-linux-musl/Dockerfile
index 385f71e5b9dd8..d8ede27faaa1e 100644
--- a/ci/docker/s390x-unknown-linux-musl/Dockerfile
+++ b/ci/docker/s390x-unknown-linux-musl/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:25.04
+FROM ubuntu:26.04
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
     curl \
diff --git a/ci/docker/sparc64-unknown-linux-gnu/Dockerfile b/ci/docker/sparc64-unknown-linux-gnu/Dockerfile
index 728586f119545..a629171f1cff2 100644
--- a/ci/docker/sparc64-unknown-linux-gnu/Dockerfile
+++ b/ci/docker/sparc64-unknown-linux-gnu/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:25.04
+FROM ubuntu:26.04
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
     ca-certificates \
diff --git a/ci/docker/wasm32-unknown-emscripten/Dockerfile b/ci/docker/wasm32-unknown-emscripten/Dockerfile
index e068ad59f94c2..1fe5d72a9539b 100644
--- a/ci/docker/wasm32-unknown-emscripten/Dockerfile
+++ b/ci/docker/wasm32-unknown-emscripten/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:25.04
+FROM ubuntu:26.04
 
 # This is a workaround to avoid the interaction with tzdata.
 ENV DEBIAN_FRONTEND=noninteractive
diff --git a/ci/docker/wasm32-wasip1/Dockerfile b/ci/docker/wasm32-wasip1/Dockerfile
index 4da0e17554f8c..26ec34ce59175 100644
--- a/ci/docker/wasm32-wasip1/Dockerfile
+++ b/ci/docker/wasm32-wasip1/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:25.04
+FROM ubuntu:26.04
 
 COPY wasi.sh /
 RUN /wasi.sh
diff --git a/ci/docker/wasm32-wasip2/Dockerfile b/ci/docker/wasm32-wasip2/Dockerfile
index a240928fa1ae9..6db3d139f0ccb 100644
--- a/ci/docker/wasm32-wasip2/Dockerfile
+++ b/ci/docker/wasm32-wasip2/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:25.04
+FROM ubuntu:26.04
 
 COPY wasi.sh /
 RUN /wasi.sh
diff --git a/ci/docker/x86_64-linux-android/Dockerfile b/ci/docker/x86_64-linux-android/Dockerfile
index 76b80a894b2bb..bc9580e6e1c0d 100644
--- a/ci/docker/x86_64-linux-android/Dockerfile
+++ b/ci/docker/x86_64-linux-android/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:25.04
+FROM ubuntu:26.04
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
     ca-certificates \
diff --git a/ci/docker/x86_64-unknown-linux-gnu/Dockerfile b/ci/docker/x86_64-unknown-linux-gnu/Dockerfile
index ed9734ca2b6f8..5b5c86ffad8d7 100644
--- a/ci/docker/x86_64-unknown-linux-gnu/Dockerfile
+++ b/ci/docker/x86_64-unknown-linux-gnu/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:25.04
+FROM ubuntu:26.04
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
     ca-certificates \
diff --git a/ci/docker/x86_64-unknown-linux-gnux32/Dockerfile b/ci/docker/x86_64-unknown-linux-gnux32/Dockerfile
index 0d5cdd7daafb0..88a9ccfa02969 100644
--- a/ci/docker/x86_64-unknown-linux-gnux32/Dockerfile
+++ b/ci/docker/x86_64-unknown-linux-gnux32/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:25.04
+FROM ubuntu:26.04
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
     ca-certificates \
diff --git a/ci/docker/x86_64-unknown-linux-musl/Dockerfile b/ci/docker/x86_64-unknown-linux-musl/Dockerfile
index ec993efd8e65b..efc193cefaa15 100644
--- a/ci/docker/x86_64-unknown-linux-musl/Dockerfile
+++ b/ci/docker/x86_64-unknown-linux-musl/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:25.04
+FROM ubuntu:26.04
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
     ca-certificates \
diff --git a/libc-test/build.rs b/libc-test/build.rs
index 09630c2493b5f..9011a61bd3485 100644
--- a/libc-test/build.rs
+++ b/libc-test/build.rs
@@ -4164,8 +4164,8 @@ fn test_linux(target: &str) {
             // FIXME(linux): Requires >= 6.12 kernel headers.
             "mnt_ns_info" => true,
 
-            // FIXME(musl): Struct has changed for new musl versions
-            "tcp_info" if musl => true,
+            // FIXME(linux): Struct has changed in newer headers.
+            "tcp_info" if gnu || musl => true,
 
             // FIXME(musl): Supported in new musl but we don't have a new enough version in CI.
             "statx" | "statx_timestamp" if musl => true,
@@ -4338,6 +4338,15 @@ fn test_linux(target: &str) {
             // Users should use SIGSYS instead.
             "SIGUNUSED" => true,
 
+            // FIXME(linux): Deprecated sysctl constants removed from newer kernel headers.
+            "KERN_REALROOTDEV" | "VM_LAPTOP_MODE" => true,
+
+            // FIXME(linux): Values changed in newer kernel headers.
+            "SW_MAX" | "SW_CNT" => true,
+
+            // FIXME(linux): glibc exposes this without sign-extension in newer headers.
+            "MS_NOUSER" if gnu => true,
+
             // FIXME(linux): conflicts with glibc headers and is tested in
             // `linux_termios.rs` below:
             "BOTHER" | "IBSHIFT" | "TCGETS2" | "TCSETS2" | "TCSETSW2" | "TCSETSF2" => true,