diff --git a/CHANGELOG.md b/CHANGELOG.md
index 240ac07511a33..91e442ddf8734 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 ### Added
 ### Dependencies
 - OpenJDK Update (April 2024 Patch releases), update to Eclipse Temurin 11.0.23+9 ([#13406](https://github.com/opensearch-project/OpenSearch/pull/13406))
+- Upgrade BouncyCastle dependencies from 1.75 to 1.78.1 resolving [CVE-2024-30172], [CVE-2024-30171] and [CVE-2024-29857]
 
 ### Changed
 ### Deprecated
diff --git a/buildSrc/version.properties b/buildSrc/version.properties
index 973b95f0739cb..e81f527f32397 100644
--- a/buildSrc/version.properties
+++ b/buildSrc/version.properties
@@ -35,7 +35,7 @@ jetty             = 9.4.53.v20231009
 # when updating this version, you need to ensure compatibility with:
 #  - plugins/ingest-attachment (transitive dependency, check the upstream POM)
 #  - distribution/tools/plugin-cli
-bouncycastle=1.75
+bouncycastle=1.78.1
 # test dependencies
 randomizedrunner  = 2.7.1
 junit             = 4.13.2
diff --git a/plugins/ingest-attachment/licenses/bcmail-jdk15to18-1.75.jar.sha1 b/plugins/ingest-attachment/licenses/bcmail-jdk15to18-1.75.jar.sha1
deleted file mode 100644
index e6840a9b02b38..0000000000000
--- a/plugins/ingest-attachment/licenses/bcmail-jdk15to18-1.75.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-b316bcd094e3917b1ece93a6edbab93f8315fb3b
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/bcmail-jdk15to18-1.78.1.jar.sha1 b/plugins/ingest-attachment/licenses/bcmail-jdk15to18-1.78.1.jar.sha1
new file mode 100644
index 0000000000000..21374feedaa87
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/bcmail-jdk15to18-1.78.1.jar.sha1
@@ -0,0 +1 @@
+4ec9c0125a605408da16cf8758cc75b502204cbb
diff --git a/plugins/ingest-attachment/licenses/bcpkix-jdk15to18-1.75.jar.sha1 b/plugins/ingest-attachment/licenses/bcpkix-jdk15to18-1.75.jar.sha1
deleted file mode 100644
index 9181b1c3ab1b6..0000000000000
--- a/plugins/ingest-attachment/licenses/bcpkix-jdk15to18-1.75.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-f16e5252ad7a46d5eaf255231b0a5da307599082
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/bcpkix-jdk15to18-1.78.1.jar.sha1 b/plugins/ingest-attachment/licenses/bcpkix-jdk15to18-1.78.1.jar.sha1
new file mode 100644
index 0000000000000..3a1d2a1e24c96
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/bcpkix-jdk15to18-1.78.1.jar.sha1
@@ -0,0 +1 @@
+5884ee847542641d04abfbfdeca3446d0300670b
diff --git a/plugins/ingest-attachment/licenses/bcprov-jdk15to18-1.75.jar.sha1 b/plugins/ingest-attachment/licenses/bcprov-jdk15to18-1.75.jar.sha1
deleted file mode 100644
index 9911bb75f9209..0000000000000
--- a/plugins/ingest-attachment/licenses/bcprov-jdk15to18-1.75.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-df22e1b6a9f6b218913f5b68dd16641344397fe0
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/bcprov-jdk15to18-1.78.1.jar.sha1 b/plugins/ingest-attachment/licenses/bcprov-jdk15to18-1.78.1.jar.sha1
new file mode 100644
index 0000000000000..393c2246b2756
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/bcprov-jdk15to18-1.78.1.jar.sha1
@@ -0,0 +1 @@
+83bfa8229f7127d933161aefb281e54a9ffcf9f4