CVE-2023-52881Public exploitNetwork attack vector

TCP stream injection via ghost ACK acceptance

Published May 29, 2024 · Updated Aug 5, 2026

TCP ACK validation in affected Linux kernel releases allows remote attackers to inject data into established flows via spoofed segments. tcp_ack in net/ipv4/tcp_input.c accepts acknowledgments for bytes that were never sent, allowing their payload to enter the socket receive queue. A listening TCP service and a spoofable source address are required; injected data can bypass IP-based trust and disclose, alter, or disrupt application traffic.

CVSS severity9.8
Critical
EPSS probability0.61%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

TCP ACK validation in affected Linux kernel releases allows remote attackers to inject data into established flows via spoofed segments. tcp_ack in net/ipv4/tcp_input.c accepts acknowledgments for bytes that were never sent, allowing their payload to enter the socket receive queue. A listening TCP service and a spoofable source address are required; injected data can bypass IP-based trust and disclose, alter, or disrupt application traffic.

The record

CVE
CVE-2023-52881
Published
May 29, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 29, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record 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=2ee4432e82437a7c051c254b065fbf5d4581e1a3
  2. Affected versionversion=3.0.58 <3.1
  3. Affected versionversion=3.2.37 <3.3
  4. Affected versionversion=3.4.25 <3.5
  5. Affected versionversion=354e4aa391ed50a4d827ff6fc11e0667d0859b25 <008b807fe487e0b15a3a6c39add4eb477f73e440
  6. Affected versionversion=354e4aa391ed50a4d827ff6fc11e0667d0859b25 <0d4e0afdd6658cd21dd5be61880411a2553fd1fc
  7. Affected versionversion=354e4aa391ed50a4d827ff6fc11e0667d0859b25 <2087d53a66e97a5eb5d1bf558d5bef9e5f891757
  8. Affected versionversion=354e4aa391ed50a4d827ff6fc11e0667d0859b25 <3d501dd326fb1c73f1b8206d4c6e1d7b15c07e27
  9. Affected versionversion=354e4aa391ed50a4d827ff6fc11e0667d0859b25 <458f07ffeccd17f99942311e09ef574ddf4a414a
  10. Affected versionversion=354e4aa391ed50a4d827ff6fc11e0667d0859b25 <69eae75ca5255e876628ac5cee9eaab31f644b57
  11. Affected versionversion=354e4aa391ed50a4d827ff6fc11e0667d0859b25 <7ffff0cc929fdfc62a74b384c4903d6496c910f0
  12. Affected versionversion=354e4aa391ed50a4d827ff6fc11e0667d0859b25 <b17a886ed29f3b70b78ccf632dad03e0c69e3c1a
  13. Affected versionversion=3.8
  14. Affected versionversion=8d15569e14cfcf9151e9e3b4c0cb98369943a2bb
  15. Affected versionversion=e252bbd8c87b95e9cecdc01350fbb0b46a0f9bf1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2ee4432e82437a7c051c254b065fbf5d4581e1a3; version=3.0.58 <3.1; version=3.2.37 <3.3; version=3.4.25 <3.5; version=354e4aa391ed50a4d827ff6fc11e0667d0859b25 <008b807fe487e0b15a3a6c39add4eb477f73e440; version=354e4aa391ed50a4d827ff6fc11e0667d0859b25 <0d4e0afdd6658cd21dd5be61880411a2553fd1fc; version=354e4aa391ed50a4d827ff6fc11e0667d0859b25 <2087d53a66e97a5eb5d1bf558d5bef9e5f891757; version=354e4aa391ed50a4d827ff6fc11e0667d0859b25 <3d501dd326fb1c73f1b8206d4c6e1d7b15c07e27; version=354e4aa391ed50a4d827ff6fc11e0667d0859b25 <458f07ffeccd17f99942311e09ef574ddf4a414a; version=354e4aa391ed50a4d827ff6fc11e0667d0859b25 <69eae75ca5255e876628ac5cee9eaab31f644b57; version=354e4aa391ed50a4d827ff6fc11e0667d0859b25 <7ffff0cc929fdfc62a74b384c4903d6496c910f0; version=354e4aa391ed50a4d827ff6fc11e0667d0859b25 <b17a886ed29f3b70b78ccf632dad03e0c69e3c1a; version=3.8; version=8d15569e14cfcf9151e9e3b4c0cb98369943a2bb; version=e252bbd8c87b95e9cecdc01350fbb0b46a0f9bf1

Published CVSS scores

5.5CanonicalCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
9.8Linux kernel CNACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 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 exploitPublished

Weakness, pattern, technique

T1190Exploit Public-Facing Application

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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