diff --git a/src/basic/fd-util.h b/src/basic/fd-util.h
index 6aecb91fab..4a02d92078 100644
--- a/src/basic/fd-util.h
+++ b/src/basic/fd-util.h
@@ -8,6 +8,8 @@
 #include <sys/socket.h>
 
 #include "macro.h"
+#include "format-util.h"
+#include "process-util.h"
 #include "stdio-util.h"
 
 /* maximum length of fdname */
@@ -112,14 +114,17 @@ static inline int dir_fd_is_root_or_cwd(int dir_fd) {
         return dir_fd == AT_FDCWD ? true : path_is_root_at(dir_fd, NULL);
 }
 
-/* The maximum length a buffer for a /proc/self/fd/<fd> path needs */
+/* The maximum length a buffer for a /proc/<pid>/fd/<fd> path needs. We intentionally don't use /proc/self/fd
+ * as these paths might be read by other programs (for example when mounting file descriptors the source path
+ * ends up in /proc/mounts and related files) for which /proc/self/fd will be interpreted differently than
+ * /proc/<pid>/fd. */
 #define PROC_FD_PATH_MAX \
-        (STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int))
+        (STRLEN("/proc//fd/") + DECIMAL_STR_MAX(pid_t) + DECIMAL_STR_MAX(int))
 
 static inline char *format_proc_fd_path(char buf[static PROC_FD_PATH_MAX], int fd) {
         assert(buf);
         assert(fd >= 0);
-        assert_se(snprintf_ok(buf, PROC_FD_PATH_MAX, "/proc/self/fd/%i", fd));
+        assert_se(snprintf_ok(buf, PROC_FD_PATH_MAX, "/proc/" PID_FMT "/fd/%i", getpid_cached(), fd));
         return buf;
 }
 
diff --git a/src/test/test-fd-util.c b/src/test/test-fd-util.c
index 20d412f5c6..1674758e6b 100644
--- a/src/test/test-fd-util.c
+++ b/src/test/test-fd-util.c
@@ -382,11 +382,16 @@ TEST(close_all_fds) {
 }
 
 TEST(format_proc_fd_path) {
-        assert_se(streq_ptr(FORMAT_PROC_FD_PATH(0), "/proc/self/fd/0"));
-        assert_se(streq_ptr(FORMAT_PROC_FD_PATH(1), "/proc/self/fd/1"));
-        assert_se(streq_ptr(FORMAT_PROC_FD_PATH(2), "/proc/self/fd/2"));
-        assert_se(streq_ptr(FORMAT_PROC_FD_PATH(3), "/proc/self/fd/3"));
-        assert_se(streq_ptr(FORMAT_PROC_FD_PATH(2147483647), "/proc/self/fd/2147483647"));
+        _cleanup_free_ char *expected = NULL;
+
+        for (int i = 0; i < 4; i++) {
+                assert_se(asprintf(&expected, "/proc/" PID_FMT "/fd/%i", getpid_cached(), i) >= 0);
+                assert_se(streq_ptr(FORMAT_PROC_FD_PATH(i), expected));
+                expected = mfree(expected);
+        }
+
+        assert_se(asprintf(&expected, "/proc/" PID_FMT "/fd/2147483647", getpid_cached()) >= 0);
+        assert_se(streq_ptr(FORMAT_PROC_FD_PATH(2147483647), expected));
 }
 
 TEST(fd_reopen) {