diff --git a/src/pyinfra/operations/server.py b/src/pyinfra/operations/server.py
index da6a34d68..69f1309c0 100644
--- a/src/pyinfra/operations/server.py
+++ b/src/pyinfra/operations/server.py
@@ -8,7 +8,6 @@
 import os
 from io import StringIO
 from itertools import filterfalse, tee
-from pathlib import Path
 from time import sleep
 from typing import TYPE_CHECKING
 
@@ -949,7 +948,9 @@ def read_any_pub_key_file(key):
         if state.cwd:
             try_path = os.path.join(state.cwd, key)
 
-        if Path(try_path).exists():
+        # NOTE: os.path.exists swallows OSError (eg ENAMETOOLONG from long inline
+        # keys), whereas Path.exists re-raises it on Python < 3.14.
+        if os.path.exists(try_path):
             with open(try_path) as f:
                 return [key.strip() for key in f.readlines()]
 
diff --git a/tests/conftest.py b/tests/conftest.py
index 7456b1c2d..808fb2e1c 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,3 +1,5 @@
+import errno
+import os
 from pathlib import Path
 from unittest.mock import patch
 
@@ -6,16 +8,34 @@
 from pyinfra_testing.util import patch_files as _patch_files
 
 
+def _check_name_too_long(filename):
+    # Real filesystems reject path components over NAME_MAX (255 bytes) with
+    # ENAMETOOLONG, eg when an inline SSH key is tried as a file path.
+    for component in str(filename).split(os.sep):
+        if len(os.fsencode(component)) > 255:
+            raise OSError(errno.ENAMETOOLONG, os.strerror(errno.ENAMETOOLONG), str(filename))
+
+
 class patch_files(_patch_files):
     """
     Extend ``pyinfra_testing.util.patch_files`` to also patch ``pathlib.Path``
     methods, now that pyinfra itself uses pathlib for local filesystem access.
     """
 
+    def exists(self, filename, *args):
+        # os.path.exists swallows OSError (eg ENAMETOOLONG) and returns False.
+        try:
+            _check_name_too_long(filename)
+        except OSError:
+            return False
+        return super().exists(filename, *args)
+
     def __enter__(self):
         patch_self = self
 
         def _path_exists(p):
+            # Path.exists re-raises ENAMETOOLONG on Python < 3.14.
+            _check_name_too_long(p)
             return patch_self.exists(str(p))
 
         def _path_is_file(p):
diff --git a/tests/operations/server.user_authorized_keys/long_inline_key_not_a_file.yaml b/tests/operations/server.user_authorized_keys/long_inline_key_not_a_file.yaml
new file mode 100644
index 000000000..d40c8083f
--- /dev/null
+++ b/tests/operations/server.user_authorized_keys/long_inline_key_not_a_file.yaml
@@ -0,0 +1,27 @@
+# Long inline public keys must not be treated as files: on Python < 3.14
+# Path.exists() raises OSError (ENAMETOOLONG) for such values, see
+# https://github.com/pyinfra-dev/pyinfra/issues/1907
+args:
+  - someuser
+kwargs:
+  public_keys:
+    - ssh-rsa AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA bob
+facts:
+  server.Home:
+    user=someuser: /home/someuser
+  files.Directory:
+    path=/home/someuser/.ssh:
+      user: someuser
+      group: someuser
+      mode: 700
+  files.File:
+    path=/home/someuser/.ssh/authorized_keys:
+      user: someuser
+      group: someuser
+      mode: 600
+  server.AuthorizedKeys:
+    path=/home/someuser/.ssh/authorized_keys, user=someuser: []
+  files.FindInFile:
+    extended_regex=False, interpolate_variables=False, path=/home/someuser/.ssh/authorized_keys, pattern=^.*ssh-rsa AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA bob.*$: []
+commands:
+  - "( [ $(tail -c1 /home/someuser/.ssh/authorized_keys | wc -l) -eq 0 ] && echo ; echo 'ssh-rsa AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA bob' ) >> /home/someuser/.ssh/authorized_keys"