CVE-2024-39496: debian linux Use-After-Free — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: btrfs: zoned: fix use-after-free due to race with dev replace While loading a zone's info during creation of a block group, we can race with a device replace operation and then trigger a use-after-free on the device that was just replaced (source device of the replace operation). This happens because at btrfs_load_zone_info() we extract a device from the chunk map into a local variable and then use the device while not under the protection of the device replace rwsem. So if there's a device replace operation happening when we extract the device and that device is the source of the replace operation, we will trigger a use-after-free if before we finish using the device the replace operation finishes and frees the device. Fix this by enlarging the critical section under the protection of the device replace rwsem so that all uses of the device are done inside the critical section.

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CVSS v3.1 Score

7.8

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Weakness Type (CWE)

CWE-416 Use After Free

Affected Products

Vendor	Product	Versions
debian	debian_linux	All
linux	linux_kernel	5.12 — 6.1.95
linux	linux_kernel	6.2 — 6.6.35
linux	linux_kernel	6.7 — 6.9.6

References

Advisories & Patches

https://git.kernel.org/stable/c/0090d6e1b210551e63cf43958dc7a1ec942cdde9 https://git.kernel.org/stable/c/092571ef9a812566c8f2c9038d9c2a64c49788d6 https://git.kernel.org/stable/c/17765964703b88d8befd899f8501150bb7e07e43 https://git.kernel.org/stable/c/a0cc006f4214b87e70983c692e05bb36c59b5752 https://git.kernel.org/stable/c/0090d6e1b210551e63cf43958dc7a1ec942cdde9 https://git.kernel.org/stable/c/092571ef9a812566c8f2c9038d9c2a64c49788d6 https://git.kernel.org/stable/c/17765964703b88d8befd899f8501150bb7e07e43 https://git.kernel.org/stable/c/a0cc006f4214b87e70983c692e05bb36c59b5752

Other References

https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html

Frequently Asked Questions

What is CVE-2024-39496? +

In the Linux kernel, the following vulnerability has been resolved: btrfs: zoned: fix use-after-free due to race with dev replace While loading a zone's info during creation of a block group, we can race with a device replace operation and then trigger a use-after-free on the device that was just replaced (source device of the replace operation). This happens because at btrfs_load_zone_info() we extract a device from the chunk map into a local variable and then use the device while not under the protection of the device replace rwsem. So if there's a device replace operation happening when we extract the device and that device is the source of the replace operation, we will trigger a use-after-free if before we finish using the device the replace operation finishes and frees the device. Fix this by enlarging the critical section under the protection of the device replace rwsem so that all uses of the device are done inside the critical section. It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2024-39496? +

CVE-2024-39496 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2024-39496? +

CVE-2024-39496 affects products from debian, linux, specifically: debian_linux, linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2024-39496? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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