CVE-2025-38057Network attack vector

Remote denial of service via leaked packet buffers

Published Jun 18, 2025 · Updated Aug 5, 2026

Memory leak in Linux kernel ESP-in-TCP processing allows remote attackers to exhaust kernel memory via crafted tunnel traffic. The IPv4 and IPv6 esp_output_tcp_finish paths fail to free an skb when TCP socket lookup fails, while espintcp_queue_out also leaves it allocated when the outbound queue exceeds max_backlog. Exploitation requires a configured ESP-in-TCP security association; a remote peer can close its TCP connection or drive reply traffic until the host reaches OOM, and retained references can hang network-namespace teardown.

CVSS severity7.5
High
EPSS probability0.44%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory leak in Linux kernel ESP-in-TCP processing allows remote attackers to exhaust kernel memory via crafted tunnel traffic. The IPv4 and IPv6 esp_output_tcp_finish paths fail to free an skb when TCP socket lookup fails, while espintcp_queue_out also leaves it allocated when the outbound queue exceeds max_backlog. Exploitation requires a configured ESP-in-TCP security association; a remote peer can close its TCP connection or drive reply traffic until the host reaches OOM, and retained references can hang network-namespace teardown.

The record

CVE
CVE-2025-38057
Published
Jun 18, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-401, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 18, 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

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=5.6
  2. Affected versionversion=e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <05db2b850a2b8b17f3d1799f563ea1d550e05ed5
  3. Affected versionversion=e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <28756f22de48d25256ed89234b66b9037a3f0157
  4. Affected versionversion=e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <63c1f19a3be3169e51a5812d22a6d0c879414076
  5. Affected versionversion=e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <d8d79cf8c2b7475c22f9874eb844bcc80f858b13
  6. Affected versionversion=e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <e2e1f50fc5ebd2826c4e8c558dc65434382d0c0b
  7. Affected versionversion=e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <eb058693dfc93ed7a9c365adb899fedd648b9d9f

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.6; version=e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <05db2b850a2b8b17f3d1799f563ea1d550e05ed5; version=e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <28756f22de48d25256ed89234b66b9037a3f0157; version=e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <63c1f19a3be3169e51a5812d22a6d0c879414076; version=e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <d8d79cf8c2b7475c22f9874eb844bcc80f858b13; version=e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <e2e1f50fc5ebd2826c4e8c558dc65434382d0c0b; version=e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <eb058693dfc93ed7a9c365adb899fedd648b9d9f

Published CVSS scores

5.5Oracle LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.5Linux kernel CNACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.5NIST NVDCVSS: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

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-401Missing Release of Memory after Effective Lifetime
T1499.004Application or System Exploitation

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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