CVE-2019-18276

Priority
Description
An issue was discovered in disable_priv_mode in shell.c in GNU Bash through
5.0 patch 11. By default, if Bash is run with its effective UID not equal
to its real UID, it will drop privileges by setting its effective UID to
its real UID. However, it does so incorrectly. On Linux and other systems
that support "saved UID" functionality, the saved UID is not dropped. An
attacker with command execution in the shell can use "enable -f" for
runtime loading of a new builtin, which can be a shared object that calls
setuid() and therefore regains privileges. However, binaries running with
an effective UID of 0 are unaffected.
Notes
mdeslauras of 2020-06-05, the development patch listed below has not
been commited to a stable bash release yet. Marking as
deferred.
Package
Source: bash (LP Ubuntu Debian)
Upstream:needs-triage
Ubuntu 12.04 ESM (Precise Pangolin):deferred (2020-06-05)
Ubuntu 14.04 ESM (Trusty Tahr):deferred (2020-06-05)
Ubuntu 16.04 LTS (Xenial Xerus):deferred (2020-06-05)
Ubuntu 18.04 LTS (Bionic Beaver):deferred (2020-06-05)
Ubuntu 20.04 LTS (Focal Fossa):deferred (2020-06-05)
Ubuntu 20.10 (Groovy Gorilla):deferred (2020-06-05)
Patches:
Upstream:https://git.savannah.gnu.org/cgit/bash.git/commit/?h=devel&id=951bdaad7a18cc0dc1036bba86b18b90874d39ff
More Information

Updated: 2020-07-28 18:56:05 UTC (commit 7b6828437fde0509248708fcdb5b0f7587b85bd1)