CVE-2021-3899

highpriority · track · 41EPSS 0.004 · 32 %ileexploit · PoCEUUS

grimoire priorityP1 · Urgent

Exploitable?

Public exploit

1 exploit · PoC

Likely / severe?

0.38% (32nd) EPSS

CVSS 7.8 · high

Is it mine?

6 products

Check your exposure

Who says so?

3 sources

cnnvd · enisa_euvd · nvd

EPSS · scored 2026-10-27

There is a race condition in the 'replaced executable' detection that, with the correct local configuration, allow an attacker to execute arbitrary code as root.

cvss

Technical severity, 0–10. One row per scoring source.

7.8

010

base score 0–10 · higher = more severe · hover a vector to decode

v3.17.8highCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 1.8 · impact 5.9

v3.17.8highCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsecondary · ENISA EU

v3.17.8highCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsecondaryexploitability 1.8 · impact 5.9

v3.17.4highCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:Psecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: no · Technical Impact: totalcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-367US

exploits (1)

Public proof-of-concept and weaponised exploit code.

liumuqing/CVE-2021-3899_PoCrace condition in apport lead to Local Privilege Escalation on UbuntuPoC · poc_in_github

affected products (6)

Products and version ranges known to be affected.

Canonical Ltd. Apport0 → 2.21.0enisa_euvdEU
canonical apport< 2.21.0nvdUScpe:2.3:a:canonical:apport:*:*:*:*:*:*:*:*
canonical ubuntu linux= 18.04nvdUScpe:2.3:o:canonical:ubuntu_linux:*:*:*:*:*:*:*:*
canonical ubuntu linux= 20.04nvdUScpe:2.3:o:canonical:ubuntu_linux:*:*:*:*:*:*:*:*
canonical ubuntu linux= 21.10nvdUScpe:2.3:o:canonical:ubuntu_linux:*:*:*:*:*:*:*:*
canonical ubuntu linux= 22.04nvdUScpe:2.3:o:canonical:ubuntu_linux:*:*:*:*:*:*:*:*

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd nvd NVD CVE.org MITRE

published 2024-06-03modified 2026-06-17

references (16)

External citations — patches, advisories, analysis.

scry

Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.

Free scan