CVE-2019-19726 : OpenBSD through 6.6 allows local users to escalate to root because a check for L

OpenBSD through 6.6 allows local users to escalate to root because a check for LD_LIBRARY_PATH in setuid programs can be defeated by setting a very small RLIMIT_DATA resource limit. When executing chpass or passwd (which are setuid root), _dl_setup_env in ld.so tries to strip LD_LIBRARY_PATH from the environment, but fails when it cannot allocate memory. Thus, the attacker is able to execute their own library code as root.

Published 2019-12-12 01:15:11

Updated 2023-10-06 17:15:11

Source MITRE

View at NVD, CVE.org

Products affected by CVE-2019-19726

Openbsd » Openbsd
Versions up to, including, (<=) 6.6
cpe:2.3:o:openbsd:openbsd:*:*:*:*:*:*:*:*
Matching versions

Exploit prediction scoring system (EPSS) score for CVE-2019-19726

EPSS FAQ

0.06%

Probability of exploitation activity in the next 30 days EPSS Score History

~ 21 %

Percentile, the proportion of vulnerabilities that are scored at or less

Metasploit modules for CVE-2019-19726

OpenBSD Dynamic Loader chpass Privilege Escalation

Disclosure Date: 2019-12-11

First seen: 2020-04-26

exploit/openbsd/local/dynamic_loader_chpass_privesc

This module exploits a vulnerability in the OpenBSD `ld.so` dynamic loader (CVE-2019-19726). The `_dl_getenv()` function fails to reset the `LD_LIBRARY_PATH` environment variable when set with approximately `ARG_MAX` colons. This can be abused to

More information

CVSS scores for CVE-2019-19726

Base Score	Base Severity	CVSS Vector	Exploitability Score	Impact Score	Score Source
7.2	HIGH	AV:L/AC:L/Au:N/C:C/I:C/A:C	3.9	10.0	NIST
Access Vector: Local Access Complexity: Low Authentication: None Confidentiality Impact: Complete Integrity Impact: Complete Availability Impact: Complete
7.8	HIGH	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H	1.8	5.9	NIST
Attack Vector: Local Attack Complexity: Low Privileges Required: Low User Interaction: None Scope: Unchanged Confidentiality: High Integrity: High Availability: High

CWE ids for CVE-2019-19726

CWE-269 Improper Privilege Management

The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor.

Assigned by: nvd@nist.gov (Primary)

References for CVE-2019-19726

http://packetstormsecurity.com/files/174986/glibc-ld.so-Local-Privilege-Escalation.html

glibc ld.so Local Privilege Escalation ≈ Packet Storm

CVEs referencing this url
http://seclists.org/fulldisclosure/2019/Dec/31

Full Disclosure: Local Privilege Escalation in OpenBSD's dynamic loader (CVE-2019-19726)
Exploit;Mailing List;Third Party Advisory
http://packetstormsecurity.com/files/155658/Qualys-Security-Advisory-OpenBSD-Dynamic-Loader-Privilege-Escalation.html

Qualys Security Advisory - OpenBSD Dynamic Loader Privilege Escalation ≈ Packet Storm
Exploit;Third Party Advisory;VDB Entry
https://www.openwall.com/lists/oss-security/2019/12/11/9

oss-security - Local Privilege Escalation in OpenBSD's dynamic loader (CVE-2019-19726)
Mailing List;Third Party Advisory
http://seclists.org/fulldisclosure/2023/Oct/11

Full Disclosure: CVE-2023-4911: Local Privilege Escalation in the glibc's ld.so

CVEs referencing this url
http://www.openwall.com/lists/oss-security/2023/10/03/2

oss-security - CVE-2023-4911: Local Privilege Escalation in the glibc's ld.so

CVEs referencing this url
https://seclists.org/bugtraq/2019/Dec/25

Bugtraq: Local Privilege Escalation in OpenBSD's dynamic loader (CVE-2019-19726)
Exploit;Mailing List;Third Party Advisory
https://www.openbsd.org/errata66.html

OpenBSD 6.6 Errata
Patch;Vendor Advisory

CVEs referencing this url
http://packetstormsecurity.com/files/155764/OpenBSD-Dynamic-Loader-chpass-Privilege-Escalation.html

OpenBSD Dynamic Loader chpass Privilege Escalation ≈ Packet Storm
Third Party Advisory;VDB Entry

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