diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index d24b1bb0cabb191690cc86ca034cb214bcb1d6bf..9f3f681d867d2b91d86478bdfdf131d372888d28 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -18,7 +18,7 @@ before_script:
   # yamllint disable rule:line-length
   - echo "deb-src http://ftp.halifax.rwth-aachen.de/debian/ bullseye main" > /etc/apt/sources.list.d/bullseye_src.list
   - echo "deb-src http://ftp.halifax.rwth-aachen.de/debian/ bullseye-updates main" >> /etc/apt/sources.list.d/bullseye_src.list
-  - echo "deb-src http://security.debian.org/ bullseye/updates main" >> /etc/apt/sources.list.d/bullseye_src.list
+  - echo "deb-src http://security.debian.org/ bullseye-security main" >> /etc/apt/sources.list.d/bullseye_src.list
   # yamllint enable rule:line-length
   - apt-get update
   - apt-get install -y apt-utils