diff --git a/httpie/output/ui/man_pages.py b/httpie/output/ui/man_pages.py
index 0ba4974578..117563ff35 100644
--- a/httpie/output/ui/man_pages.py
+++ b/httpie/output/ui/man_pages.py
@@ -27,7 +27,7 @@ def is_available(program: str) -> bool:
             stdout=subprocess.DEVNULL,
             stderr=subprocess.DEVNULL
         )
-    except Exception:
+    except OSError:
         # There might be some errors outside the process, e.g
         # a permission error to execute something that is not an
         # executable.
diff --git a/httpie/utils.py b/httpie/utils.py
index 4735b2be5d..3cb42883e5 100644
--- a/httpie/utils.py
+++ b/httpie/utils.py
@@ -190,14 +190,17 @@ def _max_age_to_expires(cookies, now):
     Translate `max-age` into `expires` for Requests to take it into account.
 
     HACK/FIXME: <https://github.com/psf/requests/issues/5743>
-
     """
     for cookie in cookies:
         if 'expires' in cookie:
             continue
         max_age = cookie.get('max-age')
-        if max_age and max_age.isdigit():
-            cookie['expires'] = now + float(max_age)
+        if max_age:
+            match = re.match(r'^([-+]?)(\d+)$', max_age)
+            if match:
+                sign, digits = match.groups()
+                sign_value = -1 if sign == '-' else 1
+                cookie['expires'] = now + sign_value * int(digits)
 
 
 def parse_content_type_header(header):
diff --git a/tests/test_sessions.py b/tests/test_sessions.py
index aa5243487d..9fd4eba733 100644
--- a/tests/test_sessions.py
+++ b/tests/test_sessions.py
@@ -442,6 +442,54 @@ def test_get_expired_cookies_using_max_age(self):
     def test_get_expired_cookies_manages_multiple_cookie_headers(self, cookies, now, expected_expired):
         assert get_expired_cookies(cookies, now=now) == expected_expired
 
+    @pytest.mark.parametrize(
+        'cookies, now, expected_expired',
+        [
+            # Negative max-age means the cookie expired N seconds ago
+            # (RFC 6265 § 5.2.2), so it must be treated as expired now.
+            (
+                'session=abc; Max-Age=-300; path=/; domain=.example.com; HttpOnly',
+                None,
+                [{'name': 'session', 'path': '/'}],
+            ),
+            # An explicitly positive max-age in the future is NOT expired.
+            (
+                'session=abc; Max-Age=300; path=/; domain=.example.com; HttpOnly',
+                None,
+                [],
+            ),
+            # An explicitly positive max-age in the past (more than N seconds
+            # ago) IS expired.
+            (
+                # Clock is in 1970 (well before the max-age is reached), so a
+                # 10-second max-age is in the future and the cookie is not yet
+                # expired.
+                'session=abc; Max-Age=10; path=/; domain=.example.com; HttpOnly',
+                100.0,
+                [],
+            ),
+            (
+                # max-age=0 with a non-zero clock: cookie expired exactly at
+                # `now`, so the expiry is <= now and it is treated as
+                # expired.
+                'session=abc; Max-Age=0; path=/; domain=.example.com; HttpOnly',
+                100.0,
+                [{'name': 'session', 'path': '/'}],
+            ),
+            # A bare '-' with no digits is not a number and must be ignored
+            # rather than raising.
+            (
+                'session=abc; Max-Age=-; path=/; domain=.example.com; HttpOnly',
+                None,
+                [],
+            ),
+        ],
+    )
+    def test_get_expired_cookies_handles_signed_max_age(
+        self, cookies, now, expected_expired,
+    ):
+        assert get_expired_cookies(cookies, now=now) == expected_expired
+
 
 class TestCookieStorage(CookieTestBase):