diff --git a/CHANGELOG.md b/CHANGELOG.md
index dedbcacf4..624f72d2a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -49,6 +49,7 @@
 - Allow finishing builds on OS X <10.13.6 (previously builds would fail at the `codesign` step)
 - The pkg-config file now uses pkg-config variables
 - The default values for the extra_completionsdir, extra_functionsdir and extra_confdir options now use the installation prefix instead of hardcoding `/usr/local`
+- A new CMake variable `FISH_USE_SYSTEM_PCRE2` controls whether fish builds with the system-installed PCRE2, or the version it bundles. By default it prefers the system library if available, unless Mac codesigning is enabled (#6952).
 
 ---
 
diff --git a/cmake/PCRE2.cmake b/cmake/PCRE2.cmake
index d96197113..84f720d0d 100644
--- a/cmake/PCRE2.cmake
+++ b/cmake/PCRE2.cmake
@@ -7,16 +7,37 @@ set(PCRE2_BUILD_TESTS OFF CACHE BOOL "Build tests")
 set(PCRE2_BUILD_PCRE2GREP OFF CACHE BOOL "Build pcre2grep")
 
 set(PCRE2_MIN_VERSION 10.21)
-IF (NOT APPLE)
-  find_library(PCRE2_LIB pcre2-${PCRE2_WIDTH})
-  find_path(PCRE2_INCLUDE_DIR pcre2.h)
+
+# Look for a system-installed PCRE2.
+find_library(SYS_PCRE2_LIB pcre2-${PCRE2_WIDTH})
+find_path(SYS_PCRE2_INCLUDE_DIR pcre2.h)
+
+# We can either use the system-installed PCRE or our bundled version.
+# This is controlled by the cache variable FISH_USE_SYSTEM_PCRE2.
+# Here we compute the default value for that variable.
+if ((APPLE) AND (MAC_CODESIGN_ID))
+  # On Mac, a codesigned fish will refuse to load a non-codesigned PCRE2
+  # (e.g. from Homebrew) so default to bundled PCRE2.
+  set(USE_SYS_PCRE2_DEFAULT OFF)
+elseif((NOT SYS_PCRE2_LIB) OR (NOT SYS_PCRE2_INCLUDE_DIR))
+  # We did not find system PCRE2, so default to bundled.
+  set(USE_SYS_PCRE2_DEFAULT OFF)
+else()
+  # Default to using the system PCRE2, which was found.
+  set(USE_SYS_PCRE2_DEFAULT ON)
 endif()
-IF (PCRE2_LIB AND PCRE2_INCLUDE_DIR)
-  message(STATUS "Found system PCRE2 library ${PCRE2_INCLUDE_DIR}")
+
+set(FISH_USE_SYSTEM_PCRE2 ${USE_SYS_PCRE2_DEFAULT} CACHE BOOL
+  "Use PCRE2 from the system, instead of bundled with fish")
+
+if(FISH_USE_SYSTEM_PCRE2)
+  set(PCRE2_LIB "${SYS_PCRE2_LIB}")
+  set(PCRE2_INCLUDE_DIR "${SYS_PCRE2_INCLUDE_DIR}")
+  message(STATUS "Using system PCRE2 library ${PCRE2_INCLUDE_DIR}")
 else()
   message(STATUS "Using bundled PCRE2 library")
   add_subdirectory(pcre2 EXCLUDE_FROM_ALL)
   set(PCRE2_INCLUDE_DIR ${CMAKE_BINARY_DIR}/pcre2)
   set(PCRE2_LIB pcre2-${PCRE2_WIDTH})
-endif(PCRE2_LIB AND PCRE2_INCLUDE_DIR)
+endif(FISH_USE_SYSTEM_PCRE2)
 include_directories(${PCRE2_INCLUDE_DIR})