Linux: Use After Free
CVE-2024-41096 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 0ae40b2d0a5de6b045504098e365d4fdff5bbeba, ff1121d2214b794dc1772081f27bdd90721a84bc, 45fc8d20e0768ab0a0ad054081d0f68aa3c83976 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 0.24% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 0ae40b2d0a5de6b045504098e365d4fdff5bbeba or ff1121d2214b794dc1772081f27bdd90721a84bc or 45fc8d20e0768ab0a0ad054081d0f68aa3c83976 or 9eee5330656bf92f51cb1f09b2dc9f8cf975b3d1, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.1.109 or 6.6.37 or 6.9.8, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | bf6e054e0e3fbc9614355b760e18c8a14f952a4e up to, but not including, 0ae40b2d0a5de6b045504098e365d4fdff5bbeba; bf6e054e0e3fbc9614355b760e18c8a14f952a4e up to, but not including, ff1121d2214b794dc1772081f27bdd90721a84bc; bf6e054e0e3fbc9614355b760e18c8a14f952a4e up to, but not including, 45fc8d20e0768ab0a0ad054081d0f68aa3c83976; bf6e054e0e3fbc9614355b760e18c8a14f952a4e up to, but not including, 9eee5330656bf92f51cb1f09b2dc9f8cf975b3d1; 5.17 | 0ae40b2d0a5de6b045504098e365d4fdff5bbeba, ff1121d2214b794dc1772081f27bdd90721a84bc, 45fc8d20e0768ab0a0ad054081d0f68aa3c83976, 9eee5330656bf92f51cb1f09b2dc9f8cf975b3d1 |
| Debian | Debian Linux | 11.0 | Not stated |
| Linux | Linux Kernel | 5.17 up to, but not including, 6.1.109; 6.2 up to, but not including, 6.6.37; 6.7 up to, but not including, 6.9.8 | 6.1.109, 6.6.37, 6.9.8 |
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 system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: PCI/MSI: Fix UAF in msi_capability_init KFENCE reports the following UAF: BUG: KFENCE: use-after-free read in __pci_enable_msi_range+0x2c0/0x488 Use-after-free read at 0x0000000024629571 (in kfence-#12): __pci_enable_msi_range+0x2c0/0x488 pci_alloc_irq_vectors_affinity+0xec/0x14c pci_alloc_irq_vectors+0x18/0x28 kfence-#12: 0x0000000008614900-0x00000000e06c228d, size=104, cache=kmalloc-128 allocated by task 81 on cpu 7 at 10.808142s: __kmem_cache_alloc_node+0x1f0/0x2bc kmalloc_trace+0x44/0x138 msi_alloc_desc+0x3c/0x9c msi_domain_insert_msi_desc+0x30/0x78 msi_setup_msi_desc+0x13c/0x184 __pci_enable_msi_range+0x258/0x488 pci_alloc_irq_vectors_affinity+0xec/0x14c pci_alloc_irq_vectors+0x18/0x28 freed by task 81 on cpu 7 at 10.811436s: msi_domain_free_descs+0xd4/0x10c msi_domain_free_locked.part.0+0xc0/0x1d8 msi_domain_alloc_irqs_all_locked+0xb4/0xbc pci_msi_setup_msi_irqs+0x30/0x4c __pci_enable_msi_range+0x2a8/0x488 pci_alloc_irq_vectors_affinity+0xec/0x14c pci_alloc_irq_vectors+0x18/0x28 Descriptor allocation done in: __pci_enable_msi_range msi_capability_init msi_setup_msi_desc msi_insert_msi_desc msi_domain_insert_msi_desc msi_alloc_desc ... Freed in case of failure in __msi_domain_alloc_locked() __pci_enable_msi_range msi_capability_init pci_msi_setup_msi_irqs msi_domain_alloc_irqs_all_locked msi_domain_alloc_locked __msi_domain_alloc_locked => fails msi_domain_free_locked ... That failure propagates back to pci_msi_setup_msi_irqs() in msi_capability_init() which accesses the descriptor for unmasking in the error exit path. Cure it by copying the descriptor and using the copy for the error exit path unmask operation. [ tglx: Massaged change log ]
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.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Third-party and government advisories
- lists.debian.org/debian-lts-announce/2025/01/msg00001.htmlMailing List, Third Party Advisory
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.0 High severity
Spotted an error? Tell us.