CyberSecBulletin
CVE-2024-26694NVD status: Analyzed

Linux: Double Free

Published Updated By the CyberSecBulletin desk

CVE-2024-26694 is a high-severity double free vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions ab9d4bb9a1892439b3123fc52b19e32b9cdf80ad, d24eb9a27bea8fe5237fa71be274391d9d51eff2, 353d321f63f7dbfc9ef58498cc732c9fe886a596 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.25% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to ab9d4bb9a1892439b3123fc52b19e32b9cdf80ad or d24eb9a27bea8fe5237fa71be274391d9d51eff2 or 353d321f63f7dbfc9ef58498cc732c9fe886a596, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.6.18 or 6.7.6, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux5e31b3df86ec6fbb925eee77fe2c450099c61dff up to, but not including, ab9d4bb9a1892439b3123fc52b19e32b9cdf80ad; 5e31b3df86ec6fbb925eee77fe2c450099c61dff up to, but not including, d24eb9a27bea8fe5237fa71be274391d9d51eff2; 5e31b3df86ec6fbb925eee77fe2c450099c61dff up to, but not including, 353d321f63f7dbfc9ef58498cc732c9fe886a596; 6.4ab9d4bb9a1892439b3123fc52b19e32b9cdf80ad, d24eb9a27bea8fe5237fa71be274391d9d51eff2, 353d321f63f7dbfc9ef58498cc732c9fe886a596
LinuxLinux Kernel6.4 up to, but not including, 6.6.18; 6.7 up to, but not including, 6.7.6; 6.86.6.18, 6.7.6

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Official description

In the Linux kernel, the following vulnerability has been resolved: wifi: iwlwifi: fix double-free bug The storage for the TLV PC register data wasn't done like all the other storage in the drv->fw area, which is cleared at the end of deallocation. Therefore, the freeing must also be done differently, explicitly NULL'ing it out after the free, since otherwise there's a nasty double-free bug here if a file fails to load after this has been parsed, and we get another free later (e.g. because no other file exists.) Fix that by adding the missing NULL assignment.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Double Free

The product calls free() twice on the same memory address.

How developers prevent this class of flaw

  • Choose a language that provides automatic memory management.
  • Ensure that each allocation is freed only once. After freeing a chunk, set the pointer to NULL to ensure the pointer cannot be freed again. In complicated error conditions, be sure that clean-up routines respect the state of allocation properly. If the language is object oriented, ensure that object destructors delete each chunk of memory only once.
  • Use a static analysis tool to find double free instances.

More Double Free vulnerabilities (CWE-415)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Double Free vulnerabilities

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