CVE-2023-53503
ext4: allow ext4_get_group_info() to fail
- Published
- Updated
- Reserved
- Assigned by
- Linux
Description
In the Linux kernel, the following vulnerability has been resolved: ext4: allow ext4_get_group_info() to fail Previously, ext4_get_group_info() would treat an invalid group number as BUG(), since in theory it should never happen. However, if a malicious attaker (or fuzzer) modifies the superblock via the block device while it is the file system is mounted, it is possible for s_first_data_block to get set to a very large number. In that case, when calculating the block group of some block number (such as the starting block of a preallocation region), could result in an underflow and very large block group number. Then the BUG_ON check in ext4_get_group_info() would fire, resutling in a denial of service attack that can be triggered by root or someone with write access to the block device. For a quality of implementation perspective, it's best that even if the system administrator does something that they shouldn't, that it will not trigger a BUG. So instead of BUG'ing, ext4_get_group_info() will call ext4_error and return NULL. We also add fallback code in all of the callers of ext4_get_group_info() that it might NULL. Also, since ext4_get_group_info() was already borderline to be an inline function, un-inline it. The results in a next reduction of the compiled text size of ext4 by roughly 2k.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Analyzed | 3.1 | Medium5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.16% · top 95% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.5.
Weakness
Affected products
- affected 2f2e09eb15849562aede80ed007658e4504ded26 – < 100c0ad6c04597fefeaaba2bb1827cc015d95067
- affected 2f2e09eb15849562aede80ed007658e4504ded26 – < 620a3c28221bb219b81bc0bffd065cc187494302
- affected 2f2e09eb15849562aede80ed007658e4504ded26 – < b4319e457d6e3fb33e443efeaf4634fc36e8a9ed
- affected 2f2e09eb15849562aede80ed007658e4504ded26 – < 31668cebf45adfb6283e465e641c4f5a21b07afa
- affected 2f2e09eb15849562aede80ed007658e4504ded26 – < 5354b2af34064a4579be8bc0e2f15a7b70f14b5f
- affected 3.11
- unaffected < 3.11
- unaffected 5.10.181 – ≤ 5.10.*
- unaffected 5.15.113 – ≤ 5.15.*
- unaffected 6.1.30 – ≤ 6.1.*
- unaffected 6.3.4 – ≤ 6.3.*
- unaffected 6.4 – ≤ *
References (5)
- https://git.kernel.org/stable/c/100c0ad6c04597fefeaaba2bb1827cc015d95067 (opens in a new tab)
- https://git.kernel.org/stable/c/620a3c28221bb219b81bc0bffd065cc187494302 (opens in a new tab)
- https://git.kernel.org/stable/c/b4319e457d6e3fb33e443efeaf4634fc36e8a9ed (opens in a new tab)
- https://git.kernel.org/stable/c/31668cebf45adfb6283e465e641c4f5a21b07afa (opens in a new tab)
- https://git.kernel.org/stable/c/5354b2af34064a4579be8bc0e2f15a7b70f14b5f (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
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[](https://trackcve.app/cve/CVE-2023-53503)Record last updated .