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CVE-2020-8833 Details

Description

Time-of-check Time-of-use Race Condition vulnerability on crash report ownership change in Apport allows for a possible privilege escalation opportunity. If fs.protected_symlinks is disabled, this can be exploited between the os.open and os.chown calls when the Apport cron script clears out crash files of size 0. A symlink with the same name as the deleted file can then be created upon which chown will be called, changing the file owner to root. Fixed in versions 2.20.1-0ubuntu2.23, 2.20.9-0ubuntu7.14, 2.20.11-0ubuntu8.8 and 2.20.11-0ubuntu22.

Metrics

CVSS 3.x Severity and Vector Strings:

NIST: [email protected]CVSS-B:4.7 MEDIUMVector:CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

CNA: [email protected]CVSS-B:5.6 MEDIUMVector:CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N

References to Advisories, Solutions, and Tools

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URL	Source(s)	Tag(s)
https://bugs.launchpad.net/ubuntu/+source/apport/+bug/1862933	CVE	ExploitThird Party Advisory
https://usn.ubuntu.com/4315-1/	CVE	Third Party Advisory
https://usn.ubuntu.com/4315-2/	CVE	Third Party Advisory
https://bugs.launchpad.net/ubuntu/+source/apport/+bug/1862933	[email protected]	ExploitThird Party Advisory
https://usn.ubuntu.com/4315-1/	[email protected]	Third Party Advisory
https://usn.ubuntu.com/4315-2/	[email protected]	Third Party Advisory

see all 6 references

Weakness Enumeration

CWE-ID	CWE Name	Source
CWE-367	Time-of-check Time-of-use (TOCTOU) Race Condition	[email protected]
CWE-367	Time-of-check Time-of-use (TOCTOU) Race Condition	[email protected]

Affected Products

Product	Versions
canonical ubuntu linux	14.04 16.04 18.04 19.10
CPE cpe:2.3:o:canonical:ubuntu_linux:14.04::::esm::: cpe:2.3:o:canonical:ubuntu_linux:16.04::::esm::: cpe:2.3:o:canonical:ubuntu_linux:18.04::::lts::: cpe:2.3:o:canonical:ubuntu_linux:19.10:::::::* Remediation No remediation found in references.
apport project apport	All versions
CPE cpe:2.3:a:apport_project:apport:-:::::::* Remediation No remediation found in references.

Change History

7 change records found show changes

Date	Action	Recorded By
Jun 17, 2026	CVE Modified	[email protected]
Nov 21, 2024	CVE Modified	CVE
May 14, 2024	CVE Modified	[email protected]
Oct 7, 2022	Modified Analysis	[email protected]
Jun 24, 2020	CVE Modified	[email protected]
May 4, 2020	CPE Deprecation Remap	[email protected]
Apr 30, 2020	Initial Analysis	[email protected]