From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: tomcruiseqi Date: Wed, 25 Mar 2026 02:23:45 +0800 Subject: 00478: CVE-2026-4519 Reject leading dashes in webbrowser URLs (GH-143931) (GH-146359) (cherry picked from commit 82a24a4442312bdcfc4c799885e8b3e00990f02b) Backported from Python 3.10: ad4d5ba32af4d80b0dfa2ba9d8203bfb219e60a5 Co-authored-by: Seth Michael Larson --- Lib/test/test_webbrowser.py | 5 +++++ Lib/webbrowser.py | 14 ++++++++++++++ .../2026-01-16-12-04-49.gh-issue-143930.zYC5x3.rst | 1 + 3 files changed, 20 insertions(+) create mode 100644 Misc/NEWS.d/next/Security/2026-01-16-12-04-49.gh-issue-143930.zYC5x3.rst diff --git a/Lib/test/test_webbrowser.py b/Lib/test/test_webbrowser.py index 7cbb8d0a29..ec4ba2f7ac 100644 --- a/Lib/test/test_webbrowser.py +++ b/Lib/test/test_webbrowser.py @@ -53,6 +53,11 @@ class GenericBrowserCommandTest(CommandTestMixin, unittest.TestCase): options=[], arguments=[URL]) + def test_reject_dash_prefixes(self): + browser = self.browser_class(name=CMD_NAME) + with self.assertRaises(ValueError): + browser.open(f"--key=val {URL}") + class BackgroundBrowserCommandTest(CommandTestMixin, unittest.TestCase): diff --git a/Lib/webbrowser.py b/Lib/webbrowser.py index 1a553f0e65..f00f1a712a 100755 --- a/Lib/webbrowser.py +++ b/Lib/webbrowser.py @@ -120,6 +120,12 @@ class BaseBrowser(object): def open_new_tab(self, url): return self.open(url, 2) + @staticmethod + def _check_url(url): + """Ensures that the URL is safe to pass to subprocesses as a parameter""" + if url and url.lstrip().startswith("-"): + raise ValueError(f"Invalid URL: {url}") + class GenericBrowser(BaseBrowser): """Class for all browsers started with a command @@ -136,6 +142,7 @@ class GenericBrowser(BaseBrowser): self.basename = os.path.basename(self.name) def open(self, url, new=0, autoraise=True): + self._check_url(url) cmdline = [self.name] + [arg.replace("%s", url) for arg in self.args] try: @@ -153,6 +160,7 @@ class BackgroundBrowser(GenericBrowser): background.""" def open(self, url, new=0, autoraise=True): + self._check_url(url) cmdline = [self.name] + [arg.replace("%s", url) for arg in self.args] try: @@ -219,6 +227,7 @@ class UnixBrowser(BaseBrowser): return not p.wait() def open(self, url, new=0, autoraise=True): + self._check_url(url) if new == 0: action = self.remote_action elif new == 1: @@ -319,6 +328,7 @@ class Konqueror(BaseBrowser): """ def open(self, url, new=0, autoraise=True): + self._check_url(url) # XXX Currently I know no way to prevent KFM from opening a new win. if new == 2: action = "newTab" @@ -402,6 +412,7 @@ class Grail(BaseBrowser): return 1 def open(self, url, new=0, autoraise=True): + self._check_url(url) if new: ok = self._remote("LOADNEW " + url) else: @@ -508,6 +519,7 @@ if os.environ.get("TERM"): if sys.platform[:3] == "win": class WindowsDefault(BaseBrowser): def open(self, url, new=0, autoraise=True): + self._check_url(url) try: os.startfile(url) except OSError: @@ -551,6 +563,7 @@ if sys.platform == 'darwin': self.name = name def open(self, url, new=0, autoraise=True): + self._check_url(url) assert "'" not in url # hack for local urls if not ':' in url: @@ -588,6 +601,7 @@ if sys.platform == 'darwin': self._name = name def open(self, url, new=0, autoraise=True): + self._check_url(url) if self._name == 'default': script = 'open location "%s"' % url.replace('"', '%22') # opens in default browser else: diff --git a/Misc/NEWS.d/next/Security/2026-01-16-12-04-49.gh-issue-143930.zYC5x3.rst b/Misc/NEWS.d/next/Security/2026-01-16-12-04-49.gh-issue-143930.zYC5x3.rst new file mode 100644 index 0000000000..0f27eae99a --- /dev/null +++ b/Misc/NEWS.d/next/Security/2026-01-16-12-04-49.gh-issue-143930.zYC5x3.rst @@ -0,0 +1 @@ +Reject leading dashes in URLs passed to :func:`webbrowser.open`