[CLSA-2026:1790209690] Fix CVE(s): CVE-2026-82049
Type:
security
Severity:
Important
Release date:
2026-09-24 00:28:20 UTC
Description:
* SECURITY UPDATE: tarfile PEP 706 "data"/"tar" extraction filter bypass via a hard link to a symlink. A crafted archive whose hard link names a symlink stored deeper in the archive made makelink_with_filter() call os.link() on the unresolved source; link(2) does not follow symlinks, so the extracted member became the same symlink inode under the hard link's own, shallower name, where its relative payload re-bases outside the destination. The chmod()/utime() that tarfile applies next then hit the outside file, changing its mode and mtime, and its contents became readable from inside the extracted tree (CWE-59). - debian/patches/CVE-2026-82049.patch: backport of cpython b8f23e307097552eaea2604383a12ab280520d0d (gh-157190, GH-157191, GH-157192), the 3.13-branch form of the fix; the changed line and its comment are upstream's verbatim, only re-anchored because this tree has no "unlink an existing targetpath" step before os.link(). The upstream regression test test_sneaky_hardlink_relocation is carried too, minus the @symlink_test / @os_helper.skip_unless_hardlink decorators and with os_helper.can_symlink() spelled support.can_symlink(), neither of which exists in 3.7. - The one-line fix closes only the variant where the archive carries a decoy file at the outer name, so os.path.exists(tarinfo._link_target) is true and extraction goes through os.link(). The decoy-less variant never reaches os.link() at all; under the "data" filter it is rejected by CVE-2026-11940.patch, already in this package, so the two must not be separated. - CVE-2026-82049 * The Misc/NEWS.d fragment of the upstream commit is omitted; this version ships a single Misc/NEWS file.
CVEs fixed:
Updated packages:
  • alt-python37_3.7.17-32_amd64.deb
    sha:85cec8d41c91ab5ca6d9c9871cee98d07d3501bc
  • alt-python37-debug_3.7.17-32_amd64.deb
    sha:3d176efffb07eaf6338029df52095f9883d1de9c
  • alt-python37-devel_3.7.17-32_amd64.deb
    sha:424682138efdc1922ddfbd0b33ff1921a869c25d
  • alt-python37-libs_3.7.17-32_amd64.deb
    sha:cc2d329b28f32b71c91baabdae5d2020156f1268
  • alt-python37-test_3.7.17-32_amd64.deb
    sha:6f0f910846557e1e12ce542ec3cb8f08920076a2
  • alt-python37-tkinter_3.7.17-32_amd64.deb
    sha:14fee36fa690f1aa968b3f648d43b1fbaed7acee
  • alt-python37-tools_3.7.17-32_amd64.deb
    sha:5ac1f12af312ba6b401a0faf127cbe79d80011db
Notes:
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