CVE-2019-18276

NameCVE-2019-18276
DescriptionAn 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.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
bash (PTS)jessie4.3-11+deb8u1vulnerable
jessie (security)4.3-11+deb8u2vulnerable
stretch4.4-5vulnerable
buster5.0-4vulnerable
bullseye, sid5.0-5vulnerable

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
bashsource(unstable)(unfixed)low

Notes

[buster] - bash <no-dsa> (Minor issue)
[stretch] - bash <no-dsa> (minor issue)
[jessie] - bash <no-dsa> (minor issue)
https://git.savannah.gnu.org/cgit/bash.git/commit/?h=devel&id=951bdaad7a18cc0dc1036bba86b18b90874d39ff
https://savannah.gnu.org/patch/?9822
https://bugzilla.suse.com/show_bug.cgi?id=1158028

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