CVE-2020-8831

World writable root owned lock file created in user controllable location

MEDIUM
5.5
CVSS Score
Published: April 22, 2020 at 09:15 PM UTC
Updated: June 17, 2026 at 03:27 AM UTC
2 products affected across 2 vendorsUbuntu LinuxApport

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Severity
MEDIUM5.5
Exploit prediction
EPSS 0.7%

Description

Apport creates a world writable lock file with root ownership in the world writable /var/lock/apport directory. If the apport/ directory does not exist (this is not uncommon as /var/lock is a tmpfs), it will create the directory, otherwise it will simply continue execution using the existing directory. This allows for a symlink attack if an attacker were to create a symlink at /var/lock/apport, changing apport's lock file location. This file could then be used to escalate privileges, for example. Fixed in versions 2.20.1-0ubuntu2.23, 2.20.9-0ubuntu7.14, 2.20.11-0ubuntu8.8 and 2.20.11-0ubuntu22.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

2.20.1 ≤ v < 2.20.1-0ubuntu2.232.20.11 ≤ v < 2.20.11-0ubuntu8.82.20.9 ≤ v < 2.20.9-0ubuntu7.142.20.12.20.112.20.9
Affected range stops below 2.20.1-0ubuntu2.23, so it looks safe — our inference, not a vendor statement
Affected range stops below 2.20.11-0ubuntu8.8, so it looks safe — our inference, not a vendor statement
Affected range stops below 2.20.9-0ubuntu7.14, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (3)

x_refsource_CONFIRMExploitThird Party Advisory
https://launchpad.net/bugs/1862348
x_refsource_CONFIRMThird Party Advisory
https://usn.ubuntu.com/4315-1/
Vendor Advisoryx_refsource_UBUNTUThird Party Advisory
https://usn.ubuntu.com/4315-2/

CVSS

Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-379CWE-59

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