CVE-2020-8428

System crash or one-bit disclosure via stale dentry

Published Jan 28, 2020 · Updated Aug 4, 2024

Use-after-free in Linux kernel 4.19 through 5.4 allows local users to crash the system or expose one bit of kernel-memory state. During concurrent open, rename, and parent-directory removal operations, do_last drops the directory reference before may_create_in_sticky reads its dentry and inode. The race requires local syscall access; the stale reads produce a kernel Oops or a one-bit access-decision oracle rather than arbitrary kernel-memory disclosure.

CVSS severity7.1
High
EPSS probability0.66%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Linux kernel 4.19 through 5.4 allows local users to crash the system or expose one bit of kernel-memory state. During concurrent open, rename, and parent-directory removal operations, do_last drops the directory reference before may_create_in_sticky reads its dentry and inode. The race requires local syscall access; the stale reads produce a kernel Oops or a one-bit access-decision oracle rather than arbitrary kernel-memory disclosure.

The record

CVE
CVE-2020-8428
Published
Jan 28, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-416, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 28, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

3.6NIST NVDAV:L/AC:L/Au:N/C:P/I:N/A:P
7.1UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
7.1NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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