diff --git a/src/analyses/libraryFunctions.ml b/src/analyses/libraryFunctions.ml
index 2eb68dd437..912867d319 100644
--- a/src/analyses/libraryFunctions.ml
+++ b/src/analyses/libraryFunctions.ml
@@ -103,7 +103,7 @@ let c_descs_list: (string * LibraryDesc.t) list = LibraryDsl.[
     ("vfprintf", unknown [drop "stream" [r_deep; w_deep]; drop "format" [r]; drop "vlist" [r_deep]]); (* TODO: what to do with a va_list type? is r_deep correct? *)
     ("vsprintf", unknown [drop "buffer" [w]; drop "format" [r]; drop "vlist" [r_deep]]); (* TODO: what to do with a va_list type? is r_deep correct? *)
     ("vasprintf", unknown [drop "strp" [w]; drop "format" [r]; drop "ap" [r_deep]]); (* TODO: what to do with a va_list type? is r_deep correct? *)
-    ("vsprintf", unknown [drop "str" [w]; drop "format" [r]; drop "ap" [r_deep]]); (* TODO: what to do with a va_list type? is r_deep correct? *)
+    ("vsnprintf", unknown [drop "str" [w]; drop "size" []; drop "format" [r]; drop "ap" [r_deep]]); (* TODO: what to do with a va_list type? is r_deep correct? *)
     ("mktime", unknown [drop "tm" [r;w]]);
     ("ctime", unknown ~attrs:[ThreadUnsafe] [drop "rm" [r]]);
     ("clearerr", unknown [drop "stream" [w]]);
@@ -1089,7 +1089,6 @@ let invalidate_actions = [
     "usleep", readsAll;
     "svc_run", writesAll;(*unsafe*)
     "dup", readsAll; (*safe*)
-    "vsnprintf", writesAllButFirst 3 readsAll; (*drop 3*)
     "__builtin___vsnprintf", writesAllButFirst 3 readsAll; (*drop 3*)
     "__builtin___vsnprintf_chk", writesAllButFirst 3 readsAll; (*drop 3*)
     "strcasecmp", readsAll; (*safe*)