diff --git a/modules/metadata/mod_cern_meta.c b/modules/metadata/mod_cern_meta.c
index a150b3c9fa1..10b5903a6a7 100644
--- a/modules/metadata/mod_cern_meta.c
+++ b/modules/metadata/mod_cern_meta.c
@@ -244,9 +244,9 @@ static int scan_meta_file(request_rec *r, apr_file_t *f)
             char *tmp;
             /* Nuke trailing whitespace */
 
-            char *endp = l + strlen(l) - 1;
-            while (endp > l && apr_isspace(*endp))
-                *endp-- = '\0';
+            char *endp = l + strlen(l);
+            while (endp > l && apr_isspace(endp[-1]))
+                *--endp = '\0';
 
             tmp = apr_pstrdup(r->pool, l);
             ap_content_type_tolower(tmp);
diff --git a/modules/proxy/mod_proxy_hcheck.c b/modules/proxy/mod_proxy_hcheck.c
index 38c5c2b5609..169dd3c24b6 100644
--- a/modules/proxy/mod_proxy_hcheck.c
+++ b/modules/proxy/mod_proxy_hcheck.c
@@ -776,8 +776,9 @@ static int hc_read_headers(request_rec *r)
         ++value;
         while (apr_isspace(*value))
             ++value;            /* Skip to start of value   */
-        for (end = &value[strlen(value)-1]; end > value && apr_isspace(*end); --end)
-            *end = '\0';
+        for (end = value + strlen(value);
+             end > value && apr_isspace(end[-1]); --end)
+            end[-1] = '\0';
         apr_table_add(r->headers_out, buffer, value);
     }
 
diff --git a/modules/proxy/mod_proxy_http.c b/modules/proxy/mod_proxy_http.c
index 970487be6ea..50e50520e2c 100644
--- a/modules/proxy/mod_proxy_http.c
+++ b/modules/proxy/mod_proxy_http.c
@@ -973,8 +973,9 @@ static apr_status_t ap_proxy_read_headers(request_rec *r, request_rec *rr,
             ++value;            /* Skip to start of value   */
 
         /* should strip trailing whitespace as well */
-        for (end = &value[strlen(value)-1]; end > value && apr_isspace(*end); --end)
-            *end = '\0';
+        for (end = value + strlen(value);
+             end > value && apr_isspace(end[-1]); --end)
+            end[-1] = '\0';
 
         /* make sure we add so as not to destroy duplicated headers
          * Modify headers requiring canonicalisation and/or affected
diff --git a/modules/proxy/mod_proxy_uwsgi.c b/modules/proxy/mod_proxy_uwsgi.c
index 26091087263..d003faaaf6d 100644
--- a/modules/proxy/mod_proxy_uwsgi.c
+++ b/modules/proxy/mod_proxy_uwsgi.c
@@ -386,9 +386,9 @@ static int uwsgi_response(request_rec *r, proxy_conn_rec * backend,
         }
         while (apr_isspace(*value))
             ++value;
-        for (end = &value[strlen(value) - 1];
-             end > value && apr_isspace(*end); --end)
-            *end = '\0';
+        for (end = value + strlen(value);
+             end > value && apr_isspace(end[-1]); --end)
+            end[-1] = '\0';
         if (*ap_scan_http_field_content(value)) {
             /* invalid value */
             len = -1;
diff --git a/server/util_script.c b/server/util_script.c
index 6a18aec8c90..d794c7b3208 100644
--- a/server/util_script.c
+++ b/server/util_script.c
@@ -649,9 +649,9 @@ AP_DECLARE(int) ap_scan_script_header_err_core_ex(request_rec *r, char *buffer,
 
             /* Nuke trailing whitespace */
 
-            char *endp = l + strlen(l) - 1;
-            while (endp > l && apr_isspace(*endp)) {
-                *endp-- = '\0';
+            char *endp = l + strlen(l);
+            while (endp > l && apr_isspace(endp[-1])) {
+                *--endp = '\0';
             }
 
             tmp = apr_pstrdup(r->pool, l);
diff --git a/test/modules/proxy/test_03_response.py b/test/modules/proxy/test_03_response.py
index 60a4afa8af9..5c22528debd 100644
--- a/test/modules/proxy/test_03_response.py
+++ b/test/modules/proxy/test_03_response.py
@@ -16,6 +16,16 @@ def _make_response(self, data):
             return """HTTP/1.1 200 OK\r\nContent-Type: 
             text/html\x00extra\r\n\r\n""".encode()
 
+        if "/empty-header" in path:
+            body = b"Hello"
+            return (
+                b"HTTP/1.1 200 OK\r\n"
+                b"X-Empty:\r\n"
+                b"Content-Length: 5\r\n"
+                b"\r\n"
+                + body
+            )
+
         if "/forwarded" in path:
             headers = data.split(b"\r\n\r\n")[0].decode("latin-1")
             forwarded = []
@@ -89,6 +99,13 @@ def test_proxy_03_001(self, env):
             lognos=["AH01106", "AH10404"]
         )
 
+    # empty backend response header values are valid
+    def test_proxy_03_004(self, env):
+        r = env.curl_get(env.mkurl("http", "test1", "/empty-header"))
+        assert r.response["status"] == 200
+        assert "x-empty" in r.response["header"]
+        assert r.response["body"] == b"Hello"
+
     # checks X-Forwarded headers
     def test_proxy_03_002(self, env):
         if not env.httpd_is_at_least("2.4.54"):
diff --git a/test/modules/proxy/test_05_uwsgi.py b/test/modules/proxy/test_05_uwsgi.py
index b0733aba7dd..0b360b89ff6 100644
--- a/test/modules/proxy/test_05_uwsgi.py
+++ b/test/modules/proxy/test_05_uwsgi.py
@@ -17,6 +17,17 @@ def hello(data):
             + body
         )
 
+    @staticmethod
+    def empty_header(data):
+        body = b"Hello"
+        return (
+            b"HTTP/1.1 200 OK\r\n"
+            b"X-Empty:\r\n"
+            b"Content-Length: 5\r\n"
+            b"\r\n"
+            + body
+        )
+
 
 class TestProxyUwsgi:
 
@@ -51,3 +62,11 @@ def test_proxy_005_01(self, env, _class_scope):
         assert data[3] == 0x00  # standard WSGI request
         assert len(data) == 4 + datasize
 
+    # empty backend response header values are valid
+    def test_proxy_005_02(self, env, _class_scope):
+        _class_scope._make_response = _UWSGIFaker.empty_header
+        r = env.curl_get(env.mkurl("http", "test1", "/"))
+        assert r.response["status"] == 200
+        assert "x-empty" in r.response["header"]
+        assert r.response["body"] == b"Hello"
+