CVE-2024-47699: linux kernel Null Dereference — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix potential null-ptr-deref in nilfs_btree_insert() Patch series "nilfs2: fix potential issues with empty b-tree nodes". This series addresses three potential issues with empty b-tree nodes that can occur with corrupted filesystem images, including one recently discovered by syzbot. This patch (of 3): If a b-tree is broken on the device, and the b-tree height is greater than 2 (the level of the root node is greater than 1) even if the number of child nodes of the b-tree root is 0, a NULL pointer dereference occurs in nilfs_btree_prepare_insert(), which is called from nilfs_btree_insert(). This is because, when the number of child nodes of the b-tree root is 0, nilfs_btree_do_lookup() does not set the block buffer head in any of path[x].bp_bh, leaving it as the initial value of NULL, but if the level of the b-tree root node is greater than 1, nilfs_btree_get_nonroot_node(), which accesses the buffer memory of path[x].bp_bh, is called. Fix this issue by adding a check to nilfs_btree_root_broken(), which performs sanity checks when reading the root node from the device, to detect this inconsistency. Thanks to Lizhi Xu for trying to solve the bug and clarifying the cause early on.

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CVSS v3.1 Score

5.5

MEDIUM

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

Weakness Type (CWE)

CWE-476 CWE-476

Affected Products

Vendor	Product	Versions
linux	linux_kernel	2.6.30 — 5.10.227
linux	linux_kernel	5.11 — 5.15.168
linux	linux_kernel	5.16 — 6.1.113
linux	linux_kernel	6.2 — 6.6.54
linux	linux_kernel	6.7 — 6.10.13
linux	linux_kernel	6.11 — 6.11.2

References

Advisories & Patches

https://git.kernel.org/stable/c/21839b6fbc3c41b3e374ecbdb0cabbbb2c53cf34 https://git.kernel.org/stable/c/24bf40740a3da6b4056721da34997ae6938f3da1 https://git.kernel.org/stable/c/3644554d308ddf2669e459a1551a7edf60b2d62b https://git.kernel.org/stable/c/73d23ecf234b7a6d47fb883f2dabe10e3230b31d https://git.kernel.org/stable/c/9403001ad65ae4f4c5de368bdda3a0636b51d51a https://git.kernel.org/stable/c/db73500d3f0e558eb642aae1d4782e7726b4a03f https://git.kernel.org/stable/c/f68523e0f26faade18833fbef577a4295d8e2c94

Other References

https://git.kernel.org/stable/c/1d94dbdfbb64cc48d10dec65cc3c4fbf2497b343 https://git.kernel.org/stable/c/2b78e9df10fb7f4e9d3d7a18417dd72fbbc1dfd0 https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html https://cert-portal.siemens.com/productcert/html/ssa-265688.html https://cert-portal.siemens.com/productcert/html/ssa-355557.html

Frequently Asked Questions

What is CVE-2024-47699? +

In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix potential null-ptr-deref in nilfs_btree_insert() Patch series "nilfs2: fix potential issues with empty b-tree nodes". This series addresses three potential issues with empty b-tree nodes that can occur with corrupted filesystem images, including one recently discovered by syzbot. This patch (of 3): If a b-tree is broken on the device, and the b-tree height is greater than 2 (the level of the root node is greater than 1) even if the number of child nodes of the b-tree root is 0, a NULL pointer dereference occurs in nilfs_btree_prepare_insert(), which is called from nilfs_btree_insert(). This is because, when the number of child nodes of the b-tree root is 0, nilfs_btree_do_lookup() does not set the block buffer head in any of path[x].bp_bh, leaving it as the initial value of NULL, but if the level of the b-tree root node is greater than 1, nilfs_btree_get_nonroot_node(), which accesses the buffer memory of path[x].bp_bh, is called. Fix this issue by adding a check to nilfs_btree_root_broken(), which performs sanity checks when reading the root node from the device, to detect this inconsistency. Thanks to Lizhi Xu for trying to solve the bug and clarifying the cause early on. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2024-47699? +

CVE-2024-47699 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2024-47699? +

CVE-2024-47699 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2024-47699? +

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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CVE-2024-47699