Vulnerability Report

CVE-2020-8833

Title: Apport Time-of-Check Time-of-Use Race Condition Privilege Escalation

Auth Bypass

Proof Of Concept

No public PoC currently indexed for CVE-2020-8833.

CWE Category CWE-367
Published Date Apr 22, 2020
Modified Date Jun 17, 2026
Exploit Status Not Found
Score 5.6 CVSS v3.1
Exploit Probability (EPSS)
0.34%

Vulnerability Summary

CVE-2020-8833: 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.

Impacted Vendors

A
apport 1
A
apport_project 1

Reference Links

https://bugs.launchpad.net/ubuntu/+source/apport/+bug/1862933 https://usn.ubuntu.com/4315-1/ https://usn.ubuntu.com/4315-2/ https://bugs.launchpad.net/ubuntu/+source/apport/+bug/1862933 https://usn.ubuntu.com/4315-1/ https://usn.ubuntu.com/4315-2/
CVSS v3.1
Source Entity [email protected]
Severity MEDIUM
5.6
Attack Vector
LOCAL
Complexity
HIGH
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
CHANGED
RAW VECTOR CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N
CVSS v3.1
Source Entity [email protected]
Severity MEDIUM
4.7
Attack Vector
LOCAL
Complexity
HIGH
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
CVSS v2.0
Source Entity [email protected]
Severity LOW
1.9
Access Vector
N/A
Authentication
N/A
RAW VECTOR AV:L/AC:M/Au:N/C:P/I:N/A:N

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2020-8833 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data or affected products updated.

PUBLISHED

Vulnerability first announced in NVD.

Attack Vector Matrix

Access Vector LOCAL
Complexity HIGH
Privileges N/A
Interaction NONE
CVSS Vector String CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N

Affected Stack

No specific products linked.