Release date:
2026-09-23 17:29:54 UTC
Description:
* SECURITY UPDATE: tarfile 'data'/'tar' extraction filter bypass via a hard
link to a symbolic link (CWE-59, link following). TarFile.makelink_with_filter()
passed tarinfo._link_target straight to os.link(); link(2) does not follow
symbolic links, so an archive storing a hard link whose target is an
archived symlink got the *same symlink inode* materialised one directory
shallower than the symlink the filter had validated. Its relative body then
re-based outside the destination directory, and the chmod()/utime() that
extraction performs on the newly created name followed the link onto the
outside file, changing its permissions and modification time; its contents
also became readable through the in-tree path. Reproduced on the patched
3.9.23 tree with a four-member archive ('x' regular decoy, 'sub/'
directory, 'sub/link' -> '../x' symlink, 'escape' hard link to 'sub/link'
with mode 0777 and mtime 946684800) extracted with filter='data': a file
outside the destination went 0600 -> 0755, its mtime was rewritten to
946684800 and its contents were readable through dest/escape. After the
fix the outside file is untouched and dest/escape is a genuine in-tree hard
link to the extracted decoy.
- debian/patches/CVE-2026-82049.patch: backport of cpython
b8f23e307097552eaea2604383a12ab280520d0d (gh-157190, GH-157191,
GH-157192), which resolves the hard-link source with os.path.realpath()
before calling os.link(), plus its regression test
test_sneaky_hardlink_relocation in Lib/test/test_tarfile.py. This
one-liner is sufficient only because CVE-2026-11940 is already applied:
it closes the variant where the archive carries a decoy at the symlink's
in-destination target so os.path.exists() is true and os.link() runs,
while the no-decoy variant skips os.link() entirely and is closed by the
guard CVE-2026-11940.patch added to makelink_with_filter(). The two must
not be separated.
- CVE-2026-82049
Updated packages:
-
alt-python39_3.9.23-30_amd64.deb
sha:f7992fbc4f59676ae52acf6a87472897358e659e
-
alt-python39-debug_3.9.23-30_amd64.deb
sha:776ea692c0a018f87e1139973bc66055114ab6cb
-
alt-python39-devel_3.9.23-30_amd64.deb
sha:bd818d7b3ed47398b26a35ad4cae757023424aaa
-
alt-python39-idle_3.9.23-30_amd64.deb
sha:1c096ddeac7ad1c8e859960c66a0e0103867f7be
-
alt-python39-libs_3.9.23-30_amd64.deb
sha:415ac497a2b6bba5d186e077ba8cc36fcac306cc
-
alt-python39-test_3.9.23-30_amd64.deb
sha:fc3364ede5c888109056027d54711973b808f063
-
alt-python39-tkinter_3.9.23-30_amd64.deb
sha:f567e5645105f3fdb74234fb8c84a44fb9dfcb7c
-
alt-python39_3.9.23-30_arm64.deb
sha:e53953d381e29820d7edbfbca7cafd9727d3a13b
-
alt-python39-debug_3.9.23-30_arm64.deb
sha:df45ae05b05c2e4db3fda8269e8757c722a51941
-
alt-python39-devel_3.9.23-30_arm64.deb
sha:fc64082c5512100132ab7fc3001067808d7d1edf
-
alt-python39-idle_3.9.23-30_arm64.deb
sha:087ac7b0d1a6399ad4b69b99042b3ce12310ade0
-
alt-python39-libs_3.9.23-30_arm64.deb
sha:cc0e32a528265d2cc0b87aac233c85dc61e7ce13
-
alt-python39-test_3.9.23-30_arm64.deb
sha:ddc319602d11a7bd8df3a4db118399f7731fe023
-
alt-python39-tkinter_3.9.23-30_arm64.deb
sha:b047fb3adcd224c27892ee3999442bd832053532
Notes:
This page is generated automatically and has not been checked for errors. For clarification or
corrections please contact the
CloudLinux Packaging Team.