CVE-2020-8833

Apport race condition in crash report permissions

MEDIUM
4.7
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
MEDIUM4.7
Exploit prediction
EPSS 0.3%

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.

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://bugs.launchpad.net/ubuntu/+source/apport/+bug/1862933
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
HIGH
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-367

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