diff --git a/src/util/subprocess.h b/src/util/subprocess.h
index 545f5879b0..91a51466c5 100644
--- a/src/util/subprocess.h
+++ b/src/util/subprocess.h
@@ -36,6 +36,8 @@ Documentation for C++ subprocessing library.
 #ifndef BITCOIN_UTIL_SUBPROCESS_H
 #define BITCOIN_UTIL_SUBPROCESS_H
 
+#include <util/fs.h>
+#include <util/strencodings.h>
 #include <util/syserror.h>
 
 #include <algorithm>
@@ -1302,12 +1304,20 @@ namespace detail {
 
       // Close all the inherited fd's except the error write pipe
       if (parent_->close_fds_) {
-        int max_fd = sysconf(_SC_OPEN_MAX);
-        if (max_fd == -1) throw OSError("sysconf failed", errno);
-
-        for (int i = 3; i < max_fd; i++) {
-          if (i == err_wr_pipe_) continue;
-          close(i);
+        try {
+            std::vector<int> fds_to_close;
+            for (const auto& it : fs::directory_iterator("/proc/self/fd")) {
+                int64_t fd;
+                if (!ParseInt64(it.path().filename().native(), &fd)) continue;
+                if (fd <= 2) continue;  // leave std{in,out,err} alone
+                if (fd == err_wr_pipe_) continue;
+                fds_to_close.push_back(fd);
+            }
+            for (const int fd : fds_to_close) {
+                close(fd);
+            }
+        } catch (...) {
+            // TODO: maybe log this - but we're in a child process, so maybe non-trivial!
         }
       }