CVE-2023-3107Network attack vector

Remote kernel panic via IPv6 fragment length overflow

Published Aug 1, 2023 · Updated Jul 9, 2025

Integer overflow in FreeBSD 12.4, 13.1, and 13.2 allows remote attackers to trigger a kernel panic via crafted IPv6 fragments. The frag6.c reassembly path stores the combined fragment payload length in the 16-bit ip6_plen field without first rejecting totals above IPV6_MAXPACKET. Unauthenticated IPv6 reachability is sufficient; affected release branches panic, interrupting the host until it restarts.

CVSS severity7.5
High
EPSS probability0.65%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer overflow in FreeBSD 12.4, 13.1, and 13.2 allows remote attackers to trigger a kernel panic via crafted IPv6 fragments. The frag6.c reassembly path stores the combined fragment payload length in the 16-bit ip6_plen field without first rejecting totals above IPV6_MAXPACKET. Unauthenticated IPv6 reachability is sufficient; affected release branches panic, interrupting the host until it restarts.

The record

CVE
CVE-2023-3107
Published
Aug 1, 2023
Updated
Jul 9, 2025
Vendor
The FreeBSD Project
Product
FreeBSD
Classifications
CWE-190, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 1, 2023CVE publishedPublication date reported by the CVE source.
  2. Jul 9, 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?

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

  1. Affected versionversion=12.4-RELEASE <12.4-RELEASE-p4
  2. Affected versionversion=13.1-RELEASE <13.1-RELEASE-p9
  3. Affected versionversion=13.2-RELEASE <13.2-RELEASE-p2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The FreeBSD Project · FreeBSDversion=12.4-RELEASE <12.4-RELEASE-p4; version=13.1-RELEASE <13.1-RELEASE-p9; version=13.2-RELEASE <13.2-RELEASE-p2

Published CVSS scores

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

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-190Integer Overflow or Wraparound
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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