CVE-2019-3842

Severity: high (CVSS 7.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.2% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2019-04-09 · updated 2026-06-17
Weakness: CWE-285

Description

In systemd before v242-rc4, it was discovered that pam_systemd does not properly sanitize the environment before using the XDG_SEAT variable. It is possible for an attacker, in some particular configurations, to set a XDG_SEAT environment variable which allows for commands to be checked against polkit policies using the "allow_active" element rather than "allow_any".

Affected products

Debian Linux: 8.0
Fedoraproject Fedora: 30
Red Hat Enterprise Linux: 7.0
systemd: through 241; 242-rc1, 242-rc2, 242-rc3

References

http://lists.opensuse.org/opensuse-security-announce/2019-05/msg00062.html
http://packetstormsecurity.com/files/152610/systemd-Seat-Verification-Active-Session-Spoofing.html
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2019-3842
https://lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b%40%3Cissues.bookkeeper.apache.org%3E
https://lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4%40%3Cissues.bookkeeper.apache.org%3E
https://lists.debian.org/debian-lts-announce/2019/04/msg00022.html
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/STR36RJE4ZZIORMDXRERVBHMPRNRTHAC/
https://www.exploit-db.com/exploits/46743/
http://lists.opensuse.org/opensuse-security-announce/2019-05/msg00062.html
http://packetstormsecurity.com/files/152610/systemd-Seat-Verification-Active-Session-Spoofing.html
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2019-3842
https://lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b%40%3Cissues.bookkeeper.apache.org%3E

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