CyberSecBulletin
CVE-2024-38555NVD status: Modified

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2024-38555 is a high-severity use after 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 f6fbb8535e990f844371086ab2c1221f71f993d3, 3cb92b0ad73d3f1734e812054e698d655e9581b0, bf8aaf0ae01c27ae3c06aa8610caf91e50393396 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 0.26% 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 f6fbb8535e990f844371086ab2c1221f71f993d3 or 3cb92b0ad73d3f1734e812054e698d655e9581b0 or bf8aaf0ae01c27ae3c06aa8610caf91e50393396 or 1337ec94bc5a9eed250e33f5f5c89a28a6bfabdb, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.219 or 5.15.161 or 6.1.93 or 6.6.33, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux27c79b3a9212cf4ba634c157e07d29548181a208 up to, but not including, f6fbb8535e990f844371086ab2c1221f71f993d3; 51d138c2610a236c1ed0059d034ee4c74f452b86 up to, but not including, 3cb92b0ad73d3f1734e812054e698d655e9581b0; 51d138c2610a236c1ed0059d034ee4c74f452b86 up to, but not including, bf8aaf0ae01c27ae3c06aa8610caf91e50393396; 51d138c2610a236c1ed0059d034ee4c74f452b86 up to, but not including, 1337ec94bc5a9eed250e33f5f5c89a28a6bfabdb; 51d138c2610a236c1ed0059d034ee4c74f452b86 up to, but not including, 1d5dce5e92a70274de67a59e1e674c3267f94cd7; 51d138c2610a236c1ed0059d034ee4c74f452b86 up to, but not including, 7ac4c69c34240c6de820492c0a28a0bd1494265a; 51d138c2610a236c1ed0059d034ee4c74f452b86 up to, but not including, db9b31aa9bc56ff0d15b78f7e827d61c4a096e40; 2e5d24b3bf091802c5456dc8f8f6a6be4493c8ca; and 3 more rangesf6fbb8535e990f844371086ab2c1221f71f993d3, 3cb92b0ad73d3f1734e812054e698d655e9581b0, bf8aaf0ae01c27ae3c06aa8610caf91e50393396, 1337ec94bc5a9eed250e33f5f5c89a28a6bfabdb, 1d5dce5e92a70274de67a59e1e674c3267f94cd7, 7ac4c69c34240c6de820492c0a28a0bd1494265a
LinuxLinux Kernel5.10.20 up to, but not including, 5.10.219; 5.12 up to, but not including, 5.15.161; 5.16 up to, but not including, 6.1.93; 6.2 up to, but not including, 6.6.33; 6.7 up to, but not including, 6.8.12; 6.9 up to, but not including, 6.9.35.10.219, 5.15.161, 6.1.93, 6.6.33, 6.8.12, 6.9.3

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.

Scoring systemScoreSeverityScored by
CVSS 3.17.0HighCNA
CVSS 3.17.8HighNVD

Official description

In the Linux kernel, the following vulnerability has been resolved: net/mlx5: Discard command completions in internal error Fix use after free when FW completion arrives while device is in internal error state. Avoid calling completion handler in this case, since the device will flush the command interface and trigger all completions manually. Kernel log: ------------[ cut here ]------------ refcount_t: underflow; use-after-free. ... RIP: 0010:refcount_warn_saturate+0xd8/0xe0 ... Call Trace: <IRQ> ? __warn+0x79/0x120 ? refcount_warn_saturate+0xd8/0xe0 ? report_bug+0x17c/0x190 ? handle_bug+0x3c/0x60 ? exc_invalid_op+0x14/0x70 ? asm_exc_invalid_op+0x16/0x20 ? refcount_warn_saturate+0xd8/0xe0 cmd_ent_put+0x13b/0x160 [mlx5_core] mlx5_cmd_comp_handler+0x5f9/0x670 [mlx5_core] cmd_comp_notifier+0x1f/0x30 [mlx5_core] notifier_call_chain+0x35/0xb0 atomic_notifier_call_chain+0x16/0x20 mlx5_eq_async_int+0xf6/0x290 [mlx5_core] notifier_call_chain+0x35/0xb0 atomic_notifier_call_chain+0x16/0x20 irq_int_handler+0x19/0x30 [mlx5_core] __handle_irq_event_percpu+0x4b/0x160 handle_irq_event+0x2e/0x80 handle_edge_irq+0x98/0x230 __common_interrupt+0x3b/0xa0 common_interrupt+0x7b/0xa0 </IRQ> <TASK> asm_common_interrupt+0x22/0x40

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

The underlying weakness: Use After Free

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.

How developers prevent this class of flaw

  • Choose a language that provides automatic memory management.
  • When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.

More Use After Free vulnerabilities (CWE-416)

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 Use After Free vulnerabilities

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