CVE-2024-56633

Kernel crash via incomplete TCP BPF memory uncharging

Published Dec 27, 2024 · Updated May 11, 2026

Memory-accounting error in the Linux kernel allows local users to crash the system through TCP BPF message redirection. In tcp_bpf_sendmsg, the __SK_REDIRECT and __SK_DROP paths pre-uncharge only apply_bytes and fail to release the remaining sk_msg bytes after an error or partial drop. Low-privileged local access and a TCP BPF sockmap configuration are required; the resulting accounting imbalance triggers an inet_sock_destruct warning and can interrupt service.

CVSS severity7.8
High
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory-accounting error in the Linux kernel allows local users to crash the system through TCP BPF message redirection. In tcp_bpf_sendmsg, the __SK_REDIRECT and __SK_DROP paths pre-uncharge only apply_bytes and fail to release the remaining sk_msg bytes after an error or partial drop. Low-privileged local access and a TCP BPF sockmap configuration are required; the resulting accounting imbalance triggers an inet_sock_destruct warning and can interrupt service.

The record

CVE
CVE-2024-56633
Published
Dec 27, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 27, 2024CVE publishedPublication date reported by the CVE source.
  2. May 11, 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=4.20
  2. Affected versionversion=604326b41a6fb9b4a78b6179335decee0365cd8c <0d6cd1151e26fc7c2d5daa85e8984aaa685a1a12
  3. Affected versionversion=604326b41a6fb9b4a78b6179335decee0365cd8c <206d56f41a1509cadd06e2178c26cb830e45057d
  4. Affected versionversion=604326b41a6fb9b4a78b6179335decee0365cd8c <456f08d24afa51b5eb816c42e4ca1c44a247bd42
  5. Affected versionversion=604326b41a6fb9b4a78b6179335decee0365cd8c <5c9e3bb43a354a2245caebbbbb4a5b8c034fdd56
  6. Affected versionversion=604326b41a6fb9b4a78b6179335decee0365cd8c <905d82e6e77d16ec3e089c92b7b59a14899dfc1a
  7. Affected versionversion=604326b41a6fb9b4a78b6179335decee0365cd8c <ca70b8baf2bd125b2a4d96e76db79375c07d7ff2
  8. Affected versionversion=604326b41a6fb9b4a78b6179335decee0365cd8c <dbedc7e142df5ea238a46fdd7462c1c42cd36a10

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.20; version=604326b41a6fb9b4a78b6179335decee0365cd8c <0d6cd1151e26fc7c2d5daa85e8984aaa685a1a12; version=604326b41a6fb9b4a78b6179335decee0365cd8c <206d56f41a1509cadd06e2178c26cb830e45057d; version=604326b41a6fb9b4a78b6179335decee0365cd8c <456f08d24afa51b5eb816c42e4ca1c44a247bd42; version=604326b41a6fb9b4a78b6179335decee0365cd8c <5c9e3bb43a354a2245caebbbbb4a5b8c034fdd56; version=604326b41a6fb9b4a78b6179335decee0365cd8c <905d82e6e77d16ec3e089c92b7b59a14899dfc1a; version=604326b41a6fb9b4a78b6179335decee0365cd8c <ca70b8baf2bd125b2a4d96e76db79375c07d7ff2; version=604326b41a6fb9b4a78b6179335decee0365cd8c <dbedc7e142df5ea238a46fdd7462c1c42cd36a10

Published CVSS scores

5.5Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.8UbuntuCVSS:3.1/AV:L/AC:L/PR:L/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 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 exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

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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