Kernel crash via ext4 fsmap range underflow
Published May 2, 2025 · Updated May 11, 2026
Denial of service in the Linux kernel ext4 filesystem allows local users to crash the kernel via an FS_IOC_GETFSMAP request. ext4_getfsmap_datadev fails to revalidate the ending key after raising the starting key to s_first_data_block, so a zero end block underflows to an impossible group number. The request reaches the kernel bug only against an ext4 filesystem using 1 KiB blocks, and the demonstrated consequence is a host crash.
Summary
What happened
Denial of service in the Linux kernel ext4 filesystem allows local users to crash the kernel via an FS_IOC_GETFSMAP request. ext4_getfsmap_datadev fails to revalidate the ending key after raising the starting key to s_first_data_block, so a zero end block underflows to an impossible group number. The request reaches the kernel bug only against an ext4 filesystem using 1 KiB blocks, and the demonstrated consequence is a host crash.
The record
- CVE
- CVE-2023-53143
- Published
- May 2, 2025
- Updated
- May 11, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- May 2, 2025CVE publishedPublication date reported by the CVE source.
- May 11, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=4.13
- Affected versionversion=4a4956249dac0b9b0027949907bff0cd1a9b57fa <15ebade3266b300da9cd1edce4004fe8fd6a2b88
- Affected versionversion=4a4956249dac0b9b0027949907bff0cd1a9b57fa <1d2366624b4c19a2ba6baf67fe57f4a1b0f67c05
- Affected versionversion=4a4956249dac0b9b0027949907bff0cd1a9b57fa <a70b49dc7eee5dbe3775a650ce598e3557ff5475
- Affected versionversion=4a4956249dac0b9b0027949907bff0cd1a9b57fa <c24f838493792b5e78a3596b4ca96375aa0af4c2
- Affected versionversion=4a4956249dac0b9b0027949907bff0cd1a9b57fa <c5d7c31e17224d847a330180ec1b03bf390632b2
- Affected versionversion=4a4956249dac0b9b0027949907bff0cd1a9b57fa <c993799baf9c5861f8df91beb80e1611b12efcbd
- Affected versionversion=4a4956249dac0b9b0027949907bff0cd1a9b57fa <eb3a695aa71a514f2e7f5778e05faba3733b70a0
- Affected versionversion=4a4956249dac0b9b0027949907bff0cd1a9b57fa <f16054ac1774915160ca4e1c73ff7a269465a1b9
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Linux kernel FSMAP crash reproducerproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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