CVE-2023-30311Public exploitNetwork attack vector

TCP session interruption via NAT sequence-number leakage

Published May 28, 2024 · Updated Feb 13, 2025

TCP session hijacking in H3C Magic R365 and R100 routers allows remote attackers to interrupt active connections via spoofed packets. Their NAT implementations preserve source ports, perform insufficient reverse-path validation, and disable TCP-window tracking, allowing an off-path attacker to infer a connection, replace its mapping, and learn live sequence numbers. No authentication or user interaction is required; successful exploitation can forcibly close the targeted TCP session.

CVSS severity7.5
High
EPSS probability0.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

TCP session hijacking in H3C Magic R365 and R100 routers allows remote attackers to interrupt active connections via spoofed packets. Their NAT implementations preserve source ports, perform insufficient reverse-path validation, and disable TCP-window tracking, allowing an off-path attacker to infer a connection, replace its mapping, and learn live sequence numbers. No authentication or user interaction is required; successful exploitation can forcibly close the targeted TCP session.

The record

CVE
CVE-2023-30311
Published
May 28, 2024
Updated
Feb 13, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-400, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 28, 2024CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 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 vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

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.

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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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499Endpoint Denial of Service

Public exploit references

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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