CVE-2026-45912
Estado: En análisisMedia (5.5)—
In the Linux kernel, the following vulnerability has been resolved:
ext4: don't cache extent during splitting extent
Caching extents during the splitting process is risky, as it may result in stale extents remaining in the status tree. Moreover, in most cases, the corresponding extent block entries are likely already cached before the split happens, making caching here not particularly useful.
Assume we have an unwritten extent, and then DIO writes the first half.
First, when ext4_split_extent_at() splits this extent, it truncates the existing extent and then inserts a new one.
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During this process, this extent status entry may be shrunk, and calls to ext4_find_extent() and ext4_cache_extents() may occur, which could potentially insert the truncated range as a hole into the extent status tree. After the split is completed, this hole is not replaced with the correct status.
Then, the outer calling functions will not correct this remaining hole extent either. Finally, if we perform a delayed buffer write on this latter part, it will re-insert the delayed extent and cause an error in space accounting.
In adition, if the unwritten extent cache is not shrunk during the splitting, ext4_cache_extents() also conflicts with existing extents when caching extents. In the future, we will add checks when caching extents, which will trigger a warning. Therefore, Do not cache extents that are being split.
Detalles técnicos trazas, registros y código del informe original
[UUUUUUUUUUUUUUUU] on-disk extent U: unwritten extent [UUUUUUUUUUUUUUUU] extent status tree |<- ->| ----> dio write this range [UUUUUUU|UUUUUUUU] on-disk extent U: unwritten extent [UUUUUUU|HHHHHHHH] extent status tree H: hole
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Puntuación base: 5.5
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.16%
- Percentil entre todas las CVEs puntuadas: 5
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
CWE
- NVD-CWE-noinfo
Referencias
- https://git.kernel.org/stable/c/4c2d9dac4d328244f9365b0a1fa27ec802821820
- https://git.kernel.org/stable/c/5b1f4290453314e11cd8e15c7baa8a9b76c19b23
- https://git.kernel.org/stable/c/692103feca376ae4298c92aa8828015d20f1d87b
- https://git.kernel.org/stable/c/8302b5b4aacdbb378f7b1216bb2ee782b5142415
- https://git.kernel.org/stable/c/8b4b19a2f96348d70bfa306ef7d4a13b0bcbea79
- https://git.kernel.org/stable/c/93b2ebbbcb2e63cfc21a1946dfe91d3aa7952036
- https://git.kernel.org/stable/c/96007fd3c106aea773c1afae2d6f64cceb6da208
- https://git.kernel.org/stable/c/9a2b95cdaf07785e2739199037bd9c0863ccc1be
JSON original (NVD)
Mostrar
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: don't cache extent during splitting extent\n\nCaching extents during the splitting process is risky, as it may result\nin stale extents remaining in the status tree. Moreover, in most cases,\nthe corresponding extent block entries are likely already cached before\nthe split happens, making caching here not particularly useful.\n\nAssume we have an unwritten extent, and then DIO writes the first half.\n\n [UUUUUUUUUUUUUUUU] on-disk extent U: unwritten extent\n [UUUUUUUUUUUUUUUU] extent status tree\n |<- ->| ----> dio write this range\n\nFirst, when ext4_split_extent_at() splits this extent, it truncates the\nexisting extent and then inserts a new one. During this process, this\nextent status entry may be shrunk, and calls to ext4_find_extent() and\next4_cache_extents() may occur, which could potentially insert the\ntruncated range as a hole into the extent status tree. After the split\nis completed, this hole is not replaced with the correct status.\n\n [UUUUUUU|UUUUUUUU] on-disk extent U: unwritten extent\n [UUUUUUU|HHHHHHHH] extent status tree H: hole\n\nThen, the outer calling functions will not correct this remaining hole\nextent either. Finally, if we perform a delayed buffer write on this\nlatter part, it will re-insert the delayed extent and cause an error in\nspace accounting.\n\nIn adition, if the unwritten extent cache is not shrunk during the\nsplitting, ext4_cache_extents() also conflicts with existing extents\nwhen caching extents. In the future, we will add checks when caching\nextents, which will trigger a warning. Therefore, Do not cache extents\nthat are being split."
}
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"lastModified": "2026-06-24T14:55:11.860",
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