[PATCH 0/2] python3: fix CVE-2026-11940 and CVE-2026-11972

[PATCH 0/2] python3: fix CVE-2026-11940 and CVE-2026-11972

[Benjamin Robin (Schneider Electric)]

This series fixes the following CVEs:
 - CVE-2026-11940
 - CVE-2026-11972

Signed-off-by: Benjamin Robin (Schneider Electric) <benjamin.robin@bootlin.com>
---
Benjamin Robin (Schneider Electric) (2):
      python3: fix CVE-2026-11940
      python3: fix CVE-2026-11972

 .../python/python3/CVE-2026-11940.patch            | 67 ++++++++++++++++++++++
 .../python/python3/CVE-2026-11972.patch            | 59 +++++++++++++++++++
 meta/recipes-devtools/python/python3_3.14.6.bb     |  2 +
 3 files changed, 128 insertions(+)
---
base-commit: 832bfebbc5651dcdb36508d584be2eac076e3dde
change-id: 20260706-fix-cves-python-master-847f3cd4c18a

Best regards,
--  
Benjamin Robin (Schneider Electric) <benjamin.robin@bootlin.com>

[PATCH 1/2] python3: fix CVE-2026-11940

[Benjamin Robin (Schneider Electric)]

tarfile.extractall() with the 'data' or 'tar' filter could be bypassed
by a crafted archive where a hardlink references a symlink stored at a
deeper name than the hardlink itself.

Signed-off-by: Benjamin Robin (Schneider Electric) <benjamin.robin@bootlin.com>
---
 .../python/python3/CVE-2026-11940.patch            | 67 ++++++++++++++++++++++
 meta/recipes-devtools/python/python3_3.14.6.bb     |  1 +
 2 files changed, 68 insertions(+)

diff --git a/meta/recipes-devtools/python/python3/CVE-2026-11940.patch b/meta/recipes-devtools/python/python3/CVE-2026-11940.patch
new file mode 100644
index 000000000000..05a5802c3965
--- /dev/null
+++ b/meta/recipes-devtools/python/python3/CVE-2026-11940.patch
@@ -0,0 +1,67 @@
+From e24b4e95524fbe8cd0f46aa3292e8040f0e07c83 Mon Sep 17 00:00:00 2001
+From: "Miss Islington (bot)"
+ <31488909+miss-islington@users.noreply.github.com>
+Date: Tue, 23 Jun 2026 15:58:47 +0200
+Subject: [PATCH 1/2] gh-151558: Fix symlink escape via `tarfile`
+ hardlink-extraction fallback (GH-151559)
+
+CVE: CVE-2026-11940
+Upstream-Status: Backport [https://github.com/python/cpython/commit/27dd970bf6b17ebca7c8ed486a40ab043ed7af8f]
+
+Signed-off-by: Benjamin Robin <benjamin.robin@bootlin.com>
+---
+ Lib/tarfile.py           |  3 +++
+ Lib/test/test_tarfile.py | 24 ++++++++++++++++++++++++
+ 2 files changed, 27 insertions(+)
+
+diff --git a/Lib/tarfile.py b/Lib/tarfile.py
+index e6734db24f64..63f23490e8a1 100644
+--- a/Lib/tarfile.py
++++ b/Lib/tarfile.py
+@@ -2782,6 +2782,9 @@ def makelink_with_filter(self, tarinfo, targetpath,
+                     "makelink_with_filter: if filter_function is not None, "
+                     + "extraction_root must also not be None")
+             try:
++                filter_function(
++                    unfiltered.replace(name=tarinfo.name, deep=False),
++                    extraction_root)
+                 filtered = filter_function(unfiltered, extraction_root)
+             except _FILTER_ERRORS as cause:
+                 raise LinkFallbackError(tarinfo, unfiltered.name) from cause
+diff --git a/Lib/test/test_tarfile.py b/Lib/test/test_tarfile.py
+index d974c7d46ec1..0fc7413be8db 100644
+--- a/Lib/test/test_tarfile.py
++++ b/Lib/test/test_tarfile.py
+@@ -4344,6 +4344,30 @@ def test_sneaky_hardlink_fallback(self):
+                     self.expect_file("boom", symlink_to='../../link_here')
+                     self.expect_file("c", symlink_to='b')
+
++    @symlink_test
++    def test_sneaky_hardlink_fallback_deep(self):
++        # (CVE-2026-11940)
++        with ArchiveMaker() as arc:
++            arc.add("a/b/s", symlink_to=os.path.join("..", "escape"))
++            arc.add("s", hardlink_to=os.path.join("a", "b", "s"))
++
++        with self.check_context(arc.open(), 'data'):
++            e = self.expect_exception(
++                tarfile.LinkFallbackError,
++                "link 's' would be extracted as a copy of "
++                + "'a/b/s', which was rejected")
++            self.assertIsInstance(e.__cause__,
++                                  tarfile.LinkOutsideDestinationError)
++
++        for filter in 'tar', 'fully_trusted':
++            with self.subTest(filter), self.check_context(arc.open(), filter):
++                if not os_helper.can_symlink():
++                    self.expect_file("a/")
++                    self.expect_file("a/b/")
++                else:
++                    self.expect_file("a/b/s", symlink_to=os.path.join('..', 'escape'))
++                    self.expect_file("s", symlink_to=os.path.join('..', 'escape'))
++
+     @symlink_test
+     def test_exfiltration_via_symlink(self):
+         # (CVE-2025-4138)
+--
+2.54.0
diff --git a/meta/recipes-devtools/python/python3_3.14.6.bb b/meta/recipes-devtools/python/python3_3.14.6.bb
index 6dfd22fc0fb6..23fc152950ea 100644
--- a/meta/recipes-devtools/python/python3_3.14.6.bb
+++ b/meta/recipes-devtools/python/python3_3.14.6.bb
@@ -22,6 +22,7 @@ SRC_URI = "http://www.python.org/ftp/python/${PV}/Python-${PV}.tar.xz \
            file://0001-Avoid-shebang-overflow-on-python-config.py.patch \
            file://0001-Update-test_sysconfig-for-posix_user-purelib.patch \
            file://0001-prefer-valid-entrypoints.patch \
+           file://CVE-2026-11940.patch \
            "
 SRC_URI:append:class-native = " \
            file://0001-Lib-sysconfig.py-use-prefix-value-from-build-configu.patch \

-- 
2.54.0

[PATCH 2/2] python3: fix CVE-2026-11972

[Benjamin Robin (Schneider Electric)]

When using the "tarfile" module with a file opened in "streaming mode"
(mode="r|") the tarfile module did not properly handle EOF, making archive
parsing take exponentially longer.

Signed-off-by: Benjamin Robin (Schneider Electric) <benjamin.robin@bootlin.com>
---
 .../python/python3/CVE-2026-11972.patch            | 59 ++++++++++++++++++++++
 meta/recipes-devtools/python/python3_3.14.6.bb     |  1 +
 2 files changed, 60 insertions(+)

diff --git a/meta/recipes-devtools/python/python3/CVE-2026-11972.patch b/meta/recipes-devtools/python/python3/CVE-2026-11972.patch
new file mode 100644
index 000000000000..7dc9c6697112
--- /dev/null
+++ b/meta/recipes-devtools/python/python3/CVE-2026-11972.patch
@@ -0,0 +1,59 @@
+From 2d256d4bfd654bdcaf2d96733799be73b8ff8f69 Mon Sep 17 00:00:00 2001
+From: Petr Viktorin <encukou@gmail.com>
+Date: Tue, 23 Jun 2026 15:13:30 +0200
+Subject: [PATCH 2/2] gh-151981: Make tarfile._Stream.seek break at EOF
+ (GH-151982)
+
+CVE: CVE-2026-11972
+Upstream-Status: Backport [https://github.com/python/cpython/commit/f50bf13566189c8d0ce5a814f33eff3d89951896]
+
+Signed-off-by: Benjamin Robin <benjamin.robin@bootlin.com>
+---
+ Lib/tarfile.py           |  4 +++-
+ Lib/test/test_tarfile.py | 16 ++++++++++++++++
+ 2 files changed, 19 insertions(+), 1 deletion(-)
+
+diff --git a/Lib/tarfile.py b/Lib/tarfile.py
+index 63f23490e8a1..399f906efdff 100644
+--- a/Lib/tarfile.py
++++ b/Lib/tarfile.py
+@@ -524,7 +524,9 @@ def seek(self, pos=0):
+         if pos - self.pos >= 0:
+             blocks, remainder = divmod(pos - self.pos, self.bufsize)
+             for i in range(blocks):
+-                self.read(self.bufsize)
++                data = self.read(self.bufsize)
++                if not data:
++                    break
+             self.read(remainder)
+         else:
+             raise StreamError("seeking backwards is not allowed")
+diff --git a/Lib/test/test_tarfile.py b/Lib/test/test_tarfile.py
+index 0fc7413be8db..045377d620cc 100644
+--- a/Lib/test/test_tarfile.py
++++ b/Lib/test/test_tarfile.py
+@@ -4786,6 +4786,22 @@ def valueerror_filter(tarinfo, path):
+         with self.check_context(arc.open(errorlevel='boo!'), filtererror_filter):
+             self.expect_exception(TypeError)  # errorlevel is not int
+
++    @support.subTests('format', [tarfile.GNU_FORMAT, tarfile.PAX_FORMAT])
++    def test_getmembers_big_size(self, format):
++        # gh-151981: A loop in seek() for streaming files tried to read the
++        # declared number of blocks even at EOF
++        tinfo = tarfile.TarInfo("huge-file")
++        tinfo.size = 1 << 64
++        bio = io.BytesIO()
++        # Write header without data
++        bio.write(tinfo.tobuf(format))
++
++        # Reset & try to get contents
++        bio.seek(0)
++        with tarfile.open(fileobj=bio, mode="r|") as tar:
++            with self.assertRaises(tarfile.ReadError):
++                tar.getmembers()
++
+
+ class OverwriteTests(archiver_tests.OverwriteTests, unittest.TestCase):
+     testdir = os.path.join(TEMPDIR, "testoverwrite")
+--
+2.54.0
diff --git a/meta/recipes-devtools/python/python3_3.14.6.bb b/meta/recipes-devtools/python/python3_3.14.6.bb
index 23fc152950ea..a45a4561339f 100644
--- a/meta/recipes-devtools/python/python3_3.14.6.bb
+++ b/meta/recipes-devtools/python/python3_3.14.6.bb
@@ -23,6 +23,7 @@ SRC_URI = "http://www.python.org/ftp/python/${PV}/Python-${PV}.tar.xz \
            file://0001-Update-test_sysconfig-for-posix_user-purelib.patch \
            file://0001-prefer-valid-entrypoints.patch \
            file://CVE-2026-11940.patch \
+           file://CVE-2026-11972.patch \
            "
 SRC_URI:append:class-native = " \
            file://0001-Lib-sysconfig.py-use-prefix-value-from-build-configu.patch \

-- 
2.54.0