diff --git a/.ci_support/environment-docs.yml b/.ci_support/environment-docs.yml
index 720af185..76d16bc1 100644
--- a/.ci_support/environment-docs.yml
+++ b/.ci_support/environment-docs.yml
@@ -9,7 +9,7 @@ dependencies:
 - openmpi
 - cloudpickle =3.1.1
 - mpi4py =4.0.1
-- pyzmq =26.3.0
+- pyzmq =26.4.0
 - flux-core
 - jupyter-book =1.0.0
 - h5py =3.13.0
diff --git a/.ci_support/environment-mpich.yml b/.ci_support/environment-mpich.yml
index 1493c25a..3cd43390 100644
--- a/.ci_support/environment-mpich.yml
+++ b/.ci_support/environment-mpich.yml
@@ -6,7 +6,7 @@ dependencies:
 - mpich
 - cloudpickle =3.1.1
 - mpi4py =4.0.1
-- pyzmq =26.3.0
+- pyzmq =26.4.0
 - h5py =3.13.0
 - networkx =3.4.2
 - pygraphviz =1.14
diff --git a/.ci_support/environment-openmpi.yml b/.ci_support/environment-openmpi.yml
index 85b35b22..4e7bb246 100644
--- a/.ci_support/environment-openmpi.yml
+++ b/.ci_support/environment-openmpi.yml
@@ -6,7 +6,7 @@ dependencies:
 - openmpi
 - cloudpickle =3.1.1
 - mpi4py =4.0.1
-- pyzmq =26.3.0
+- pyzmq =26.4.0
 - h5py =3.13.0
 - networkx =3.4.2
 - pygraphviz =1.14
diff --git a/.ci_support/environment-win.yml b/.ci_support/environment-win.yml
index 3345b3f0..8eb29961 100644
--- a/.ci_support/environment-win.yml
+++ b/.ci_support/environment-win.yml
@@ -6,7 +6,7 @@ dependencies:
 - msmpi
 - cloudpickle =3.1.1
 - mpi4py =4.0.1
-- pyzmq =26.3.0
+- pyzmq =26.4.0
 - h5py =3.13.0
 - networkx =3.4.2
 - pygraphviz =1.14
diff --git a/binder/environment.yml b/binder/environment.yml
index 21e09830..328fc24c 100644
--- a/binder/environment.yml
+++ b/binder/environment.yml
@@ -6,7 +6,7 @@ dependencies:
 - openmpi
 - cloudpickle =3.1.1
 - mpi4py =4.0.1
-- pyzmq =26.3.0
+- pyzmq =26.4.0
 - flux-core =0.59.0
 - flux-pmix =0.5.0
 - versioneer =0.28
diff --git a/pyproject.toml b/pyproject.toml
index c72038e7..4029cf33 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -26,7 +26,7 @@ classifiers = [
 ]
 dependencies = [
     "cloudpickle==3.1.1",
-    "pyzmq==26.3.0",
+    "pyzmq==26.4.0",
 ]
 dynamic = ["version"]