CVE-2021-0342

Local privilege escalation via TUN packet use-after-free

Published Jan 11, 2021 · Updated Aug 3, 2024

Use-after-free in Android kernel tun_get_user allows local users with System execution privileges to escalate privileges without interaction. In IFF_NAPI_FRAGS mode, the function supplies helpers with an skb data pointer positioned at the MAC layer even though they require the network header, enabling stale-memory corruption. Reachability requires existing local System-level execution; successful exploitation raises privileges within the device rather than providing remote entry.

CVSS severity6.7
Medium
EPSS probability0.17%
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 Android kernel tun_get_user allows local users with System execution privileges to escalate privileges without interaction. In IFF_NAPI_FRAGS mode, the function supplies helpers with an skb data pointer positioned at the MAC layer even though they require the network header, enabling stale-memory corruption. Reachability requires existing local System-level execution; successful exploitation raises privileges within the device rather than providing remote entry.

The record

CVE
CVE-2021-0342
Published
Jan 11, 2021
Updated
Aug 3, 2024
Vendor
Google Cloud
Product
Android
Classifications
CWE-416, T1404
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Jan 11, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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?

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  1. Affected versionversion=Android kernel

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Google Cloud · Androidversion=Android kernel

Published CVSS scores

6.7NIST NVDCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
4.6NIST NVDAV:L/AC:L/Au:N/C:P/I:P/A:P

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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1404Exploitation for Privilege Escalation

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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