CVE-2025-38463Public exploit

Service interruption via TCP allocation overflow

Published Jul 25, 2025 · Updated Aug 5, 2026

Integer overflow in the Linux kernel allows local users to interrupt service through crafted TCP socket writes. In net/ipv4/tcp.c, unsigned promotion makes size_goal minus skb->len a large positive value, causing tcp_wmem_schedule() to overflow sk_forward_alloc. The reliable reproducer requires TCP_REPAIR privileges, while ordinary large sends can reach the same accounting wraparound when TCP window bounding reduces size_goal.

CVSS severity5.5
Medium
EPSS probability0.16%
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 the Linux kernel allows local users to interrupt service through crafted TCP socket writes. In net/ipv4/tcp.c, unsigned promotion makes size_goal minus skb->len a large positive value, causing tcp_wmem_schedule() to overflow sk_forward_alloc. The reliable reproducer requires TCP_REPAIR privileges, while ordinary large sends can reach the same accounting wraparound when TCP window bounding reduces size_goal.

The record

CVE
CVE-2025-38463
Published
Jul 25, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 25, 2025CVE 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

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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=270a1c3de47e49dd2fc18f48e46b101e48050e78 <62e6160cfb5514787bda833d466509edc38fde23
  2. Affected versionversion=270a1c3de47e49dd2fc18f48e46b101e48050e78 <81373cd1d72d87c7d844d4454a526b8f53e72d00
  3. Affected versionversion=270a1c3de47e49dd2fc18f48e46b101e48050e78 <9f164fa6bb09fbcc60fa5c3ff551ce9eec1befd7
  4. Affected versionversion=270a1c3de47e49dd2fc18f48e46b101e48050e78 <d3a5f2871adc0c61c61869f37f3e697d97f03d8c
  5. Affected versionversion=6.5

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=270a1c3de47e49dd2fc18f48e46b101e48050e78 <62e6160cfb5514787bda833d466509edc38fde23; version=270a1c3de47e49dd2fc18f48e46b101e48050e78 <81373cd1d72d87c7d844d4454a526b8f53e72d00; version=270a1c3de47e49dd2fc18f48e46b101e48050e78 <9f164fa6bb09fbcc60fa5c3ff551ce9eec1befd7; version=270a1c3de47e49dd2fc18f48e46b101e48050e78 <d3a5f2871adc0c61c61869f37f3e697d97f03d8c; version=6.5

Published CVSS scores

5.5UbuntuCVSS:3.1/AV:L/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

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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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

T1499.004Application or System Exploitation

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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