diff --git a/CHANGES.txt b/CHANGES.txt
index d638ba109e..41fe42729e 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,4 +1,5 @@
 3.11.12
+ * Update Jackson from 2.9.10 to 2.12.5 (CASSANDRA-16851)
  * Include SASI components to snapshots (CASSANDRA-15134)
  * Make assassinate more resilient to missing tokens (CASSANDRA-16847)
  * Exclude Jackson 1.x transitive dependency of hadoop* provided dependencies (CASSANDRA-16854)
diff --git a/build.xml b/build.xml
index db2d64ca5a..bab504e6c9 100644
--- a/build.xml
+++ b/build.xml
@@ -348,9 +348,9 @@
           <dependency groupId="org.slf4j" artifactId="jcl-over-slf4j" version="1.7.7" />
           <dependency groupId="ch.qos.logback" artifactId="logback-core" version="1.1.3"/>
           <dependency groupId="ch.qos.logback" artifactId="logback-classic" version="1.1.3"/>
-          <dependency groupId="com.fasterxml.jackson.core" artifactId="jackson-core" version="2.9.10"/>
-          <dependency groupId="com.fasterxml.jackson.core" artifactId="jackson-databind" version="2.9.10.8"/>
-          <dependency groupId="com.fasterxml.jackson.core" artifactId="jackson-annotations" version="2.9.10"/>
+          <dependency groupId="com.fasterxml.jackson.core" artifactId="jackson-core" version="2.12.5"/>
+          <dependency groupId="com.fasterxml.jackson.core" artifactId="jackson-databind" version="2.12.5"/>
+          <dependency groupId="com.fasterxml.jackson.core" artifactId="jackson-annotations" version="2.12.5"/>
           <dependency groupId="com.googlecode.json-simple" artifactId="json-simple" version="1.1"/>
           <dependency groupId="com.boundary" artifactId="high-scale-lib" version="1.0.6"/>
           <dependency groupId="com.github.jbellis" artifactId="jamm" version="${jamm.version}"/>