python3: Fix CVE-2026-4519 and CVE-2026-4786

Apply the upstream v3.12 fix [1], aligned with the original v3.11 fix [2],
and follow-up fix [3] to address CVE-2026-4519 by disallowing URLs with
leading dashes when invoking browser commands, as referenced in [5].

CVE-2026-4786 [6] revealed the CVE-2026-4519 fix was incomplete, as %action
in URLs could bypass dash-prefix checks. Apply follow-up fix [4], noted in
[5], to revalidate the URL after %action expansion.

[1] cbba611939
[2] ceac1efc66
[3] 96fc504860
[4] f4654824ae
[5] https://security-tracker.debian.org/tracker/CVE-2026-4519
[6] https://security-tracker.debian.org/tracker/CVE-2026-4786

References:
https://nvd.nist.gov/vuln/detail/CVE-2026-4519
https://nvd.nist.gov/vuln/detail/CVE-2026-4786

(From OE-Core rev: e6d81b3be531e97058366c81056a38c0b6fa7380)

Signed-off-by: Sudhir Dumbhare <sudumbha@cisco.com>
Signed-off-by: Yoann Congal <yoann.congal@smile.fr>
Signed-off-by: Paul Barker <paul@pbarker.dev>
This commit is contained in:
Sudhir Dumbhare
2026-06-13 03:11:37 -07:00
committed by Paul Barker
parent 703b680089
commit 1401e6e003
4 changed files with 335 additions and 0 deletions

View File

@@ -0,0 +1,66 @@
From b9af29b9f2f880cdcdc49a1460743680f59dcb4e Mon Sep 17 00:00:00 2001
From: Stan Ulbrych <stan@python.org>
Date: Mon, 13 Apr 2026 22:41:51 +0100
Subject: [PATCH] [3.11] gh-148169: Fix webbrowser `%action` substitution
bypass of dash-prefix check (GH-148170) (#148520)
CVE: CVE-2026-4519 CVE-2026-4786
Upstream-Status: Backport [https://github.com/python/cpython/commit/f4654824ae0850ac87227fb270f9057477946769]
Backport Changes:
- This file is not present in the current version and is therefore omitted.
Misc/NEWS.d/next/Security/2026-03-31-09-15-51.gh-issue-148169.EZJzz2.rst
(cherry picked from commit d22922c8a7958353689dc4763dd72da2dea03fff)
(cherry picked from commit f4654824ae0850ac87227fb270f9057477946769)
Signed-off-by: Sudhir Dumbhare <sudumbha@cisco.com>
---
Lib/test/test_webbrowser.py | 8 ++++++++
Lib/webbrowser.py | 5 +++--
2 files changed, 11 insertions(+), 2 deletions(-)
diff --git a/Lib/test/test_webbrowser.py b/Lib/test/test_webbrowser.py
index c9bf525360d..1d21f133725 100644
--- a/Lib/test/test_webbrowser.py
+++ b/Lib/test/test_webbrowser.py
@@ -103,6 +103,14 @@ class ChromeCommandTest(CommandTestMixin, unittest.TestCase):
options=[],
arguments=[URL])
+ def test_reject_action_dash_prefixes(self):
+ browser = self.browser_class(name=CMD_NAME)
+ with self.assertRaises(ValueError):
+ browser.open('%action--incognito')
+ # new=1: action is "--new-window", so "%action" itself expands to
+ # a dash-prefixed flag even with no dash in the original URL.
+ with self.assertRaises(ValueError):
+ browser.open('%action', new=1)
class EdgeCommandTest(CommandTestMixin, unittest.TestCase):
diff --git a/Lib/webbrowser.py b/Lib/webbrowser.py
index 000e89275b7..97c4eec9080 100755
--- a/Lib/webbrowser.py
+++ b/Lib/webbrowser.py
@@ -268,7 +268,6 @@ class UnixBrowser(BaseBrowser):
def open(self, url, new=0, autoraise=True):
sys.audit("webbrowser.open", url)
- self._check_url(url)
if new == 0:
action = self.remote_action
elif new == 1:
@@ -282,7 +281,9 @@ class UnixBrowser(BaseBrowser):
raise Error("Bad 'new' parameter to open(); " +
"expected 0, 1, or 2, got %s" % new)
- args = [arg.replace("%s", url).replace("%action", action)
+ self._check_url(url.replace("%action", action))
+
+ args = [arg.replace("%action", action).replace("%s", url)
for arg in self.remote_args]
args = [arg for arg in args if arg]
success = self._invoke(args, True, autoraise, url)
--
2.35.6

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@@ -0,0 +1,107 @@
From 7df48dd3c6330611a04d85a5159c0ea424dc1e62 Mon Sep 17 00:00:00 2001
From: Pinky <pinky00ch@gmail.com>
Date: Wed, 25 Mar 2026 01:02:37 +0530
Subject: [PATCH] [3.12] gh-143930: Reject leading dashes in webbrowser
URLs (GH-146360)
CVE: CVE-2026-4519
Upstream-Status: Backport [https://github.com/python/cpython/commit/cbba6119391112aba9c5aebf7b94aea447922c48]
Backport Changes:
- This file is not present in the current version and is therefore omitted
Misc/NEWS.d/next/Security/2026-01-16-12-04-49.gh-issue-143930.zYC5x3.rst
(cherry picked from commit 82a24a4442312bdcfc4c799885e8b3e00990f02b)
Co-authored-by: Seth Michael Larson <seth@python.org>
(cherry picked from commit cbba6119391112aba9c5aebf7b94aea447922c48)
Signed-off-by: Sudhir Dumbhare <sudumbha@cisco.com>
---
Lib/test/test_webbrowser.py | 5 +++++
Lib/webbrowser.py | 12 ++++++++++++
2 files changed, 17 insertions(+)
diff --git a/Lib/test/test_webbrowser.py b/Lib/test/test_webbrowser.py
index 2d695bc8831..60f094fd6a1 100644
--- a/Lib/test/test_webbrowser.py
+++ b/Lib/test/test_webbrowser.py
@@ -59,6 +59,11 @@ 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 13b9e85f9e1..0bdb644d7db 100755
--- a/Lib/webbrowser.py
+++ b/Lib/webbrowser.py
@@ -158,6 +158,12 @@ 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
@@ -175,6 +181,7 @@ class GenericBrowser(BaseBrowser):
def open(self, url, new=0, autoraise=True):
sys.audit("webbrowser.open", url)
+ self._check_url(url)
cmdline = [self.name] + [arg.replace("%s", url)
for arg in self.args]
try:
@@ -195,6 +202,7 @@ class BackgroundBrowser(GenericBrowser):
cmdline = [self.name] + [arg.replace("%s", url)
for arg in self.args]
sys.audit("webbrowser.open", url)
+ self._check_url(url)
try:
if sys.platform[:3] == 'win':
p = subprocess.Popen(cmdline)
@@ -260,6 +268,7 @@ class UnixBrowser(BaseBrowser):
def open(self, url, new=0, autoraise=True):
sys.audit("webbrowser.open", url)
+ self._check_url(url)
if new == 0:
action = self.remote_action
elif new == 1:
@@ -350,6 +359,7 @@ class Konqueror(BaseBrowser):
def open(self, url, new=0, autoraise=True):
sys.audit("webbrowser.open", url)
+ self._check_url(url)
# XXX Currently I know no way to prevent KFM from opening a new win.
if new == 2:
action = "newTab"
@@ -554,6 +564,7 @@ if sys.platform[:3] == "win":
class WindowsDefault(BaseBrowser):
def open(self, url, new=0, autoraise=True):
sys.audit("webbrowser.open", url)
+ self._check_url(url)
try:
os.startfile(url)
except OSError:
@@ -638,6 +649,7 @@ if sys.platform == 'darwin':
def open(self, url, new=0, autoraise=True):
sys.audit("webbrowser.open", url)
+ self._check_url(url)
if self.name == 'default':
script = 'open location "%s"' % url.replace('"', '%22') # opens in default browser
else:
--
2.35.6

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@@ -0,0 +1,159 @@
From 3ca64ff1722d2410a4e50e760de70f6279fa99fa Mon Sep 17 00:00:00 2001
From: "Miss Islington (bot)"
<31488909+miss-islington@users.noreply.github.com>
Date: Sat, 4 Apr 2026 00:53:49 +0200
Subject: [PATCH] [3.11] gh-143930: Tweak the exception message and
increase test coverage (GH-146476) (GH-148045) (GH-148051) (GH-148052)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
CVE: CVE-2026-4519
Upstream-Status: Backport [https://github.com/python/cpython/commit/96fc5048605863c7b6fd6289643feb0e97edd96c]
Backport Changes:
- This file is not present in the current version and is therefore omitted.
Misc/NEWS.d/next/Security/2026-01-16-12-04-49.gh-issue-143930.zYC5x3.rst
- The file introduced in v3.12 by this commit;
https://github.com/python/cpython/commit/cbba6119391112aba9c5aebf7b94aea447922c48
(cherry picked from commit cc023511238ad93ecc8796157c6f9139a2bb2932)
(cherry picked from commit 89bfb8e5ed3c7caa241028f1a4eac5f6275a46a4)
(cherry picked from commit 3681d47a440865aead912a054d4599087b4270dd)
Co-authored-by: Łukasz Langa <lukasz@langa.pl>
(cherry picked from commit 96fc5048605863c7b6fd6289643feb0e97edd96c)
Signed-off-by: Sudhir Dumbhare <sudumbha@cisco.com>
---
Lib/test/test_webbrowser.py | 81 ++++++++++++++++++++++++++++++++++---
Lib/webbrowser.py | 2 +-
2 files changed, 76 insertions(+), 7 deletions(-)
diff --git a/Lib/test/test_webbrowser.py b/Lib/test/test_webbrowser.py
index 60f094fd6a1..c9bf525360d 100644
--- a/Lib/test/test_webbrowser.py
+++ b/Lib/test/test_webbrowser.py
@@ -1,6 +1,7 @@
+import io
+import os
import webbrowser
import unittest
-import os
import sys
import subprocess
from unittest import mock
@@ -49,6 +50,14 @@ class CommandTestMixin:
popen_args.pop(popen_args.index(option))
self.assertEqual(popen_args, arguments)
+ def test_reject_dash_prefixes(self):
+ browser = self.browser_class(name=CMD_NAME)
+ with self.assertRaisesRegex(
+ ValueError,
+ r"^Invalid URL \(leading dash disallowed\): '--key=val http.*'$"
+ ):
+ browser.open(f"--key=val {URL}")
+
class GenericBrowserCommandTest(CommandTestMixin, unittest.TestCase):
@@ -59,11 +68,6 @@ 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):
@@ -224,6 +228,71 @@ class ELinksCommandTest(CommandTestMixin, unittest.TestCase):
arguments=['openURL({},new-tab)'.format(URL)])
+class MockPopenPipe:
+ def __init__(self, cmd, mode):
+ self.cmd = cmd
+ self.mode = mode
+ self.pipe = io.StringIO()
+ self._closed = False
+
+ def write(self, buf):
+ self.pipe.write(buf)
+
+ def close(self):
+ self._closed = True
+ return None
+
+
+@unittest.skipUnless(sys.platform == "darwin", "macOS specific test")
+class MacOSXOSAScriptTest(unittest.TestCase):
+ def setUp(self):
+ # Ensure that 'BROWSER' is not set to 'open' or something else.
+ # See: https://github.com/python/cpython/issues/131254.
+ env = self.enterContext(os_helper.EnvironmentVarGuard())
+ env.unset("BROWSER")
+
+ support.patch(self, os, "popen", self.mock_popen)
+ self.browser = webbrowser.MacOSXOSAScript("default")
+
+ def mock_popen(self, cmd, mode):
+ self.popen_pipe = MockPopenPipe(cmd, mode)
+ return self.popen_pipe
+
+ def test_default(self):
+ browser = webbrowser.get()
+ assert isinstance(browser, webbrowser.MacOSXOSAScript)
+ self.assertEqual(browser.name, "default")
+
+ def test_default_open(self):
+ url = "https://python.org"
+ self.browser.open(url)
+ self.assertTrue(self.popen_pipe._closed)
+ self.assertEqual(self.popen_pipe.cmd, "osascript")
+ script = self.popen_pipe.pipe.getvalue()
+ self.assertEqual(script.strip(), f'open location "{url}"')
+
+ def test_url_quote(self):
+ self.browser.open('https://python.org/"quote"')
+ script = self.popen_pipe.pipe.getvalue()
+ self.assertEqual(
+ script.strip(), 'open location "https://python.org/%22quote%22"'
+ )
+
+ def test_explicit_browser(self):
+ browser = webbrowser.MacOSXOSAScript("safari")
+ browser.open("https://python.org")
+ script = self.popen_pipe.pipe.getvalue()
+ self.assertIn('tell application "safari"', script)
+ self.assertIn('open location "https://python.org"', script)
+
+ def test_reject_dash_prefixes(self):
+ with self.assertRaisesRegex(
+ ValueError,
+ r"^Invalid URL \(leading dash disallowed\): '--key=val http.*'$"
+ ):
+ self.browser.open(f"--key=val {URL}")
+
+
class BrowserRegistrationTest(unittest.TestCase):
def setUp(self):
diff --git a/Lib/webbrowser.py b/Lib/webbrowser.py
index 0bdb644d7db..000e89275b7 100755
--- a/Lib/webbrowser.py
+++ b/Lib/webbrowser.py
@@ -162,7 +162,7 @@ class BaseBrowser(object):
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}")
+ raise ValueError(f"Invalid URL (leading dash disallowed): {url!r}")
class GenericBrowser(BaseBrowser):
--
2.35.6

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@@ -37,6 +37,9 @@ SRC_URI = "http://www.python.org/ftp/python/${PV}/Python-${PV}.tar.xz \
file://CVE-2026-1502.patch \
file://CVE-2026-6100.patch \
file://CVE-2026-3644_CVE-2026-0672.patch \
file://CVE-2026-4519_p1.patch \
file://CVE-2026-4519_p2.patch \
file://CVE-2026-4519_CVE-2026-4786.patch \
"
SRC_URI:append:class-native = " \