CVE-20XX-?
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CVE-2024-26956

7.8 HIGH 0.3% exploit odds Fix listed

What it is

In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix failure to detect DAT corruption in btree and direct mappings Patch series "nilfs2: fix kernel bug at submit_bh_wbc()". This resolves a kernel BUG reported by syzbot. Since there are two flaws involved, I've made each one a separate patch. The first patch alone resolves the syzbot-reported bug, but I think both fixes should be sent to stable, so I've tagged them as such. This patch (of 2): Syzbot has reported a kernel bug in submit_bh_wbc() when writing file data to a nilfs2 file system whose metadata is corrupted. There are two flaws involved in this issue. The first flaw is that when nilfs_get_block() locates a data block using btree or direct mapping, if the disk address translation routine nilfs_dat_translate() fails with internal code -ENOENT due to DAT metadata corruption, it can be passed back to nilfs_get_block(). This causes nilfs_get_block() to misidentify an existing block as non-existent, causing both data block lookup and insertion to fail inconsistently. The second flaw is that nilfs_get_block() returns a successful status in this inconsistent state. This causes the caller __block_write_begin_int() or others to request a read even though the buffer is not mapped, resulting in a BUG_ON check for the BH_Mapped flag in submit_bh_wbc() failing. This fixes the first issue by changing the return value to code -EINVAL when a conversion using DAT fails with code -ENOENT, avoiding the conflicting condition that leads to the kernel bug described above. Here, code -EINVAL indicates that metadata corruption was detected during the block lookup, which will be properly handled as a file system error and converted to -EIO when passing through the nilfs2 bmap layer.

At a glance

Exploitability
Can be exploited locally on the machine with a low-privilege account. High risk of data exposure, data tampering, service disruption.
Exploit odds
0.3% chance of exploitation in the next 30 days (EPSS).
Fix
A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

  1. PublishedDisclosed publicly on CVE.org and NVD
  2. Last updatedMost recent change to the record

Why it ranks here

Details

Published
Last modified
Exploit probability
0.3% · EPSS, next 30 days
Record status
Analyzed

Affected

Attack profile CVSS 3.1 · 7.8

Attack vector
Local
Complexity
Low
Privileges needed
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Raw vector

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

Is it in your code?

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Read https://cve-list.com/agent/cve/CVE-2024-26956.md and follow it. Check whether this project is affected by CVE-2024-26956. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record