diff --git a/pom.xml b/pom.xml
index ae99121..d84e7a7 100644
--- a/pom.xml
+++ b/pom.xml
@@ -31,7 +31,7 @@
     <io7m.java.targetJavaVersion>21</io7m.java.targetJavaVersion>
 
     <!-- Third-party dependencies. -->
-    <logback.version>1.5.8</logback.version>
+    <logback.version>1.5.9</logback.version>
     <slf4j.version>2.0.16</slf4j.version>
     <org.junit.version>5.11.2</org.junit.version>
   </properties>