CVE-2021-27803

Process crash via P2P peer use-after-free

Published Feb 26, 2021 · Updated Dec 18, 2025

Use-after-free in wpa_supplicant 1.0 through 2.9 allows physically proximate attackers to crash the process via crafted P2P frames. An invalid Provision Discovery Request can evict the oldest peer entry while processing continues to read and write the freed allocation. Exploitation requires CONFIG_P2P and active P2P discovery within radio range; process termination is confirmed, while code execution remains potential.

CVSS severity7.5
High
EPSS probability1.23%
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 wpa_supplicant 1.0 through 2.9 allows physically proximate attackers to crash the process via crafted P2P frames. An invalid Provision Discovery Request can evict the oldest peer entry while processing continues to read and write the freed allocation. Exploitation requires CONFIG_P2P and active P2P discovery within radio range; process termination is confirmed, while code execution remains potential.

The record

CVE
CVE-2021-27803
Published
Feb 26, 2021
Updated
Dec 18, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1499
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 26, 2021CVE publishedPublication date reported by the CVE source.
  2. Dec 18, 2025Record 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 vectoradjacent
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5CISA-ADPCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NIST NVDCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
5.4NIST NVDAV:A/AC:M/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

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

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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