CVE-2023-1206

Service interruption via IPv6 connection-table hash collisions

Published Jun 30, 2023 · Updated Oct 15, 2024

Resource exhaustion in Linux Kernel 6.5-rc1 allows remote attackers to interrupt IPv6 TCP service with colliding SYN requests. The __ipv6_addr_jhash function XORs portions of each IPv6 address before hashing, allowing chosen addresses to collide and force slow linear bucket searches. Attackers require local-network reachability or a high-bandwidth connection, and the resulting workload can consume about 95% of server CPU without altering data.

CVSS severity5.7
Medium
EPSS probability0.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Resource exhaustion in Linux Kernel 6.5-rc1 allows remote attackers to interrupt IPv6 TCP service with colliding SYN requests. The __ipv6_addr_jhash function XORs portions of each IPv6 address before hashing, allowing chosen addresses to collide and force slow linear bucket searches. Attackers require local-network reachability or a high-bandwidth connection, and the resulting workload can consume about 95% of server CPU without altering data.

The record

CVE
CVE-2023-1206
Published
Jun 30, 2023
Updated
Oct 15, 2024
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-400, T1498.001
Attack vector
adjacent
Privileges
Unavailable

Timeline

How it unfolded

  1. Jun 30, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 15, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=kernel 6.5-rc1

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linux Kernelversion=kernel 6.5-rc1

Published CVSS scores

5.7NIST NVDCVSS:3.1/AV:A/AC:L/PR:L/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)
Vectoradjacent
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1498.001Direct Network Flood

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo