diff --git a/.github/workflows/CICD.yml b/.github/workflows/CICD.yml
index 61844a84..fc807718 100644
--- a/.github/workflows/CICD.yml
+++ b/.github/workflows/CICD.yml
@@ -166,7 +166,8 @@ jobs:
           - { target: arm-unknown-linux-gnueabihf , os: ubuntu-latest , dpkg_arch: armhf,            use-cross: true }
           - { target: arm-unknown-linux-musleabihf, os: ubuntu-latest , dpkg_arch: musl-linux-armhf, use-cross: true }
           - { target: i686-pc-windows-msvc        , os: windows-2025  ,                                              }
-          - { target: i686-unknown-linux-gnu      , os: ubuntu-latest , dpkg_arch: i386,             use-cross: true }
+          # The timeout test's socketpair fails on the Ubuntu 26.04 runner.
+          - { target: i686-unknown-linux-gnu      , os: ubuntu-24.04  , dpkg_arch: i386,             use-cross: true }
           - { target: i686-unknown-linux-musl     , os: ubuntu-latest , dpkg_arch: musl-linux-i686,  use-cross: true }
           - { target: x86_64-apple-darwin         , os: macos-15-intel,                                              }
           - { target: aarch64-apple-darwin        , os: macos-latest  ,                                              }
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 91d8d49a..04f7b5ff 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 
 ## Other
 
+- Pin the i686 GNU CI runner to Ubuntu 24.04 to avoid `socketpair` failures on Ubuntu 26.04, see #4101 (@PerchAnton)
 - Fix dead Visual C++ Redistributable link in README, see #3895 (@1t1sCooL)
 - Document `StripAnsiMode` and its variants in rustdoc, see #4067 (@ump45nose)
 - Update Cargo dependencies to resolve current RustSec advisories, see #3861 (@TyceHerrman)