diff --git a/doc/release-notes/rl-2511.section.md b/doc/release-notes/rl-2511.section.md
index 316d034553bb..06a9af3df419 100644
--- a/doc/release-notes/rl-2511.section.md
+++ b/doc/release-notes/rl-2511.section.md
@@ -140,6 +140,8 @@
 - `searx` was updated to use `envsubst` instead of `sed` for parsing secrets from environment variables.
   If your previous configuration included a secret reference like `server.secret_key = "@SEARX_SECRET_KEY@"`, you must migrate to the new envsubst syntax: `server.secret_key = "$SEARX_SECRET_KEY"`.
 
+- A new hardening flag, `glibcxxassertions` was made available, corresponding to the glibc `_GLIBCXX_ASSERTIONS` option.
+
 - `versionCheckHook`: Packages that previously relied solely on `pname` to locate the program used to version check, but have a differing `meta.mainProgram` entry, might now fail.