CVE-2021-47520: can: pch_can: pch_can_rx_normal: fix use after free
First published: Fri May 24 2024(Updated: )
In the Linux kernel, the following vulnerability has been resolved: can: pch_can: pch_can_rx_normal: fix use after free After calling netif_receive_skb(skb), dereferencing skb is unsafe. Especially, the can_frame cf which aliases skb memory is dereferenced just after the call netif_receive_skb(skb). Reordering the lines solves the issue.
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux kernel | >=2.6.37<4.4.295 | |
| Linux kernel | >=4.5<4.9.293 | |
| Linux kernel | >=4.10<4.14.258 | |
| Linux kernel | >=4.15<4.19.221 | |
| Linux kernel | >=4.20<5.4.165 | |
| Linux kernel | >=5.5<5.10.85 | |
| Linux kernel | >=5.11<5.15.8 |
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Reference Links
- https://git.kernel.org/stable/c/bafe343a885c70dddf358379cf0b2a1c07355d8d
- https://git.kernel.org/stable/c/3a3c46e2eff0577454860a203be1a8295f4acb76
- https://git.kernel.org/stable/c/affbad02bf80380a7403885b9fe4a1587d1bb4f3
- https://git.kernel.org/stable/c/3e193ef4e0a3f5bf92ede83ef214cb09d01b00aa
- https://git.kernel.org/stable/c/abb4eff3dcd2e583060082a18a8dbf31f02689d4
- https://git.kernel.org/stable/c/703dde112021c93d6e89443c070e7dbd4dea612e
- https://git.kernel.org/stable/c/6c73fc931658d8cbc8a1714b326cb31eb71d16a7
- https://git.kernel.org/stable/c/94cddf1e9227a171b27292509d59691819c458db
Frequently Asked Questions
What is the severity of CVE-2021-47520?
CVE-2021-47520 is classified as a medium severity vulnerability in the Linux kernel.
How do I fix CVE-2021-47520?
To fix CVE-2021-47520, you should upgrade to a version of the Linux kernel that is not affected, specifically one that is higher than the vulnerable versions listed.
What versions of the Linux kernel are affected by CVE-2021-47520?
CVE-2021-47520 affects multiple versions of the Linux kernel, specifically from 2.6.37 up to but not including 4.4.295, 4.5 up to but not including 4.9.293, and similar ranges for subsequent releases.
What causes the vulnerability CVE-2021-47520?
The vulnerability is caused by a use-after-free condition when dereferencing the can_frame structure right after calling netif_receive_skb.
Is CVE-2021-47520 publicly known?
Yes, CVE-2021-47520 is publicly known and documented in the Common Vulnerabilities and Exposures database.
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