diff --git a/doc/changes/10115.md b/doc/changes/10115.md
new file mode 100644
index 000000000000..20d2802df9b1
--- /dev/null
+++ b/doc/changes/10115.md
@@ -0,0 +1,2 @@
+- coq: fix performance regression in coqdep unescaping (#10115, fixes
+  #10088, @ejgallego, thanks to Dan Christensen for the report)
diff --git a/src/dune_rules/coq/coq_rules.ml b/src/dune_rules/coq/coq_rules.ml
index 57335706e259..1dd5c67bf386 100644
--- a/src/dune_rules/coq/coq_rules.ml
+++ b/src/dune_rules/coq/coq_rules.ml
@@ -519,7 +519,8 @@ let coqdep_invalid phase line =
    Note that coqdep escapes a few more things, including spaces, $, #,
    [], ?, %, homedir... How to handle that seems tricky.
 *)
-let unescape_coqdep string = Re.replace_string (Re.compile (Re.str "\\:")) ~by:":" string
+let escaped_colon = Re.compile (Re.str "\\:")
+let unescape_coqdep string = Re.replace_string escaped_colon ~by:":" string
 
 let parse_line ~dir line =
   match String.lsplit2 line ~on:':' with