CVE-2019-3842

Exp

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".

Published: 2019-04-09 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2019-3842 is rated Exploit Available (52.9/100): CVSS High severity, with low exploitation likelihood (EPSS 0.10%). 3 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2019-3842

EDB-ID Source Kind Published Link
46743 exploit_db edb 2019-04-23 Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2019-3842

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-11-21 0.15% 0.10% -0.05%
2 2025-11-18 0.09% 0.15% +0.06%
3 2025-03-30 — 0.09% —

Full EPSS history (11 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2019-3842

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.0 3.1 HIGH
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.0 5.9 [email protected]
4.5 3.0 MEDIUM
CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 1.0 3.4 [email protected]
4.4 2.0 MEDIUM
AV:L/AC:M/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:L)
Requires local access to the target system.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 3.4 6.4 [email protected]

Weakness enumeration for CVE-2019-3842

OS Trackers for CVE-2019-3842

vendor priority summary link
debian not yet assigned CVE-2019-3842 not yet assigned priority: Debian including 1 source packages (systemd), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2019-3842
redhat medium — https://access.redhat.com/security/cve/CVE-2019-3842
suse medium CVE-2019-3842 severity moderate: SUSE including 615 source package names (0.1.0:libsystemd0-234-24.30.1, 0.1.0:libudev1-234-24.30.1, …), 857 product×package rows across 112 product lines (Container caasp/v4/389-ds, Container caasp/v4/busybox, … (112 product lines)): Fixed 700, Known Affected 157. https://www.suse.com/security/cve/CVE-2019-3842/
ubuntu medium CVE-2019-3842 medium priority: Ubuntu including 1 source packages (systemd), 5 status rows across 5 suites (bionic, cosmic, trusty, upstream, xenial): released 5. https://ubuntu.com/security/CVE-2019-3842

Affected software / configurations for CVE-2019-3842

Vendor Product Version Raw CPE
systemd_project systemd <= 241 cpe:2.3:a:systemd_project:systemd:*:*:*:*:*:*:*:*
systemd_project systemd 242 cpe:2.3:a:systemd_project:systemd:242:rc1:*:*:*:*:*:*
systemd_project systemd 242 cpe:2.3:a:systemd_project:systemd:242:rc2:*:*:*:*:*:*
systemd_project systemd 242 cpe:2.3:a:systemd_project:systemd:242:rc3:*:*:*:*:*:*
redhat enterprise_linux 7.0 cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
fedoraproject fedora 30 cpe:2.3:o:fedoraproject:fedora:30:*:*:*:*:*:*:*
debian debian_linux 8.0 cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*

References for CVE-2019-3842

URL Tags
http://lists.opensuse.org/opensuse-security-announce/2019-05/msg00062.html Third Party Advisory
http://packetstormsecurity.com/files/152610/systemd-Seat-Verification-Active-Session-Spoofing.html Exploit Third Party Advisory VDB Entry
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2019-3842 Issue Tracking Third Party Advisory
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 Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/STR36RJE4ZZIORMDXRERVBHMPRNRTHAC/
https://www.exploit-db.com/exploits/46743/ Exploit Third Party Advisory VDB Entry
cvelogic Threat Intelligence