CVE-2020-7462

Kernel panic via loopback IPv6 use-after-free

Published Mar 26, 2021 · Updated Aug 4, 2024

Kernel use-after-free in FreeBSD 11.4-PRERELEASE before r360733 and 11.3-RELEASE before p13 allows local users to crash the system. Kernel mbuf handling leaves freed packet memory reachable when IPv6 Hop-by-Hop options are sent through the loopback interface. Any local account with socket API access can trigger a kernel panic, interrupting every service on the host.

CVSS severity5.5
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Kernel use-after-free in FreeBSD 11.4-PRERELEASE before r360733 and 11.3-RELEASE before p13 allows local users to crash the system. Kernel mbuf handling leaves freed packet memory reachable when IPv6 Hop-by-Hop options are sent through the loopback interface. Any local account with socket API access can trigger a kernel panic, interrupting every service on the host.

The record

CVE
CVE-2020-7462
Published
Mar 26, 2021
Updated
Aug 4, 2024
Vendor
The FreeBSD Project
Product
FreeBSD
Classifications
CWE-416, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 26, 2021CVE 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=FreeBSD 11.3-RELEASE before p13

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The FreeBSD Project · FreeBSDversion=FreeBSD 11.3-RELEASE before p13

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
4.9NIST NVDAV:L/AC:L/Au:N/C:N/I:N/A:C

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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
T1499.004Endpoint Denial of Service: Application or System Exploitation

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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