🛡️ CVE-2024-26640 — debian-linux

🟠 CVSS 7.8 — High ✅ No Known Exploit NVD
7.8
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

tcp: add sanity checks to rx zerocopy

In the Linux kernel, the following vulnerability has been resolved:

tcp: add sanity checks to rx zerocopy

TCP rx zerocopy intent is to map pages initially allocated

from NIC drivers, not pages owned by a fs.

This patch adds to can_map_frag() these additional checks:

  • Page must not be a compound one.
  • page->mapping must be NULL.

This fixes the panic reported by ZhangPeng.

syzbot was able to loopback packets built with sendfile(),

mapping pages owned by an ext4 file to TCP rx zerocopy.

r3 = socket$inet_tcp(0x2, 0x1, 0x0)

mmap(&(0x7f0000ff9000/0x4000)=nil, 0x4000, 0x0, 0x12, r3, 0x0)

r4 = socket$inet_tcp(0x2, 0x1, 0x0)

bind$inet(r4, &(0x7f0000000000)={0x2, 0x4e24, @multicast1}, 0x10)

connect$inet(r4, &(0x7f00000006c0)={0x2, 0x4e24, @empty}, 0x10)

r5 = openat$dir(0xffffffffffffff9c, &(0x7f00000000c0)='./file0\x00',

0x181e42, 0x0)

fallocate(r5, 0x0, 0x0, 0x85b8)

sendfile(r4, r5, 0x0, 0x8ba0)

getsockopt$inet_tcp_TCP_ZEROCOPY_RECEIVE(r4, 0x6, 0x23,

&(0x7f00000001c0)={&(0x7f0000ffb000/0x3000)=nil, 0x3000, 0x0, 0x0, 0x0,

0x0, 0x0, 0x0, 0x0}, &(0x7f0000000440)=0x40)

r6 = openat$dir(0xffffffffffffff9c, &(0x7f00000000c0)='./file0\x00',

0x181e42, 0x0)

How this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

Affected software

CVE-2024-26640 is recorded against 3 packages.

  • debian-linux
  • kernel (from 6.7.0 up to 6.7.4)
  • linux-kernel

Timeline and source

Published on 18 March 2024 and last revised on 4 August 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from NVD.

References

git.kernel.org
git.kernel.org
git.kernel.org
git.kernel.org
git.kernel.org
git.kernel.org
git.kernel.org
git.kernel.org
git.kernel.org
git.kernel.org
git.kernel.org
git.kernel.org
lists.debian.org

CVE-2024-26640 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity HIGH
CVSS Score 7.8
CVSS Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE N/A
Public Exploit ✅ No
Source NVD
Published 2024-03-18
Updated 2026-08-12
Modified 2026-08-04

Affected Packages

Software From version Fixed in
debian-linux — —
kernel 6.7.0 6.7.4
linux-kernel — —

References

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