diff --git a/.werks/17277.md b/.werks/17277.md
new file mode 100644
index 00000000000..b91a9efd774
--- /dev/null
+++ b/.werks/17277.md
@@ -0,0 +1,17 @@
+[//]: # (werk v2)
+# check-cert: Fix checking of public key size
+
+key        | value
+---------- | ---
+date       | 2024-12-12T12:46:13+00:00
+version    | 2.4.0b1
+class      | fix
+edition    | cre
+component  | checks
+level      | 1
+compatible | yes
+
+When configuring to check the public key size of the certificate.
+check-cert would just ignore this configuration option.
+
+Now the checking works as expected.
diff --git a/cmk/plugins/collection/server_side_calls/cert.py b/cmk/plugins/collection/server_side_calls/cert.py
index bd1dda10dd9..cab5ca108ff 100644
--- a/cmk/plugins/collection/server_side_calls/cert.py
+++ b/cmk/plugins/collection/server_side_calls/cert.py
@@ -57,7 +57,7 @@ class Subject(BaseModel):
     organization: str | None = None
     org_unit: str | None = None
     pubkey_algorithm: PubKey | None = None
-    pubkey_size: str | None = None
+    pubkeysize: str | None = None
 
 
 class Certificate(BaseModel):
@@ -231,7 +231,7 @@ def _subject_args(subject: Subject, host_config: HostConfig) -> Iterator[str]:
     if (pubkey := subject.pubkey_algorithm) is not None:
         yield "--pubkey-algorithm"
         yield pubkey[0]
-    if (pubkey_size := subject.pubkey_size) is not None:
+    if (pubkey_size := subject.pubkeysize) is not None:
         yield "--pubkey-size"
         yield replace_macros(pubkey_size, host_config.macros)