CVE-2025-38627 (GCVE-0-2025-38627)
Vulnerability from cvelistv5
Published
2025-08-22 16:00
Modified
2025-08-22 16:00
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
f2fs: compress: fix UAF of f2fs_inode_info in f2fs_free_dic
The decompress_io_ctx may be released asynchronously after
I/O completion. If this file is deleted immediately after read,
and the kworker of processing post_read_wq has not been executed yet
due to high workloads, It is possible that the inode(f2fs_inode_info)
is evicted and freed before it is used f2fs_free_dic.
The UAF case as below:
Thread A Thread B
- f2fs_decompress_end_io
- f2fs_put_dic
- queue_work
add free_dic work to post_read_wq
- do_unlink
- iput
- evict
- call_rcu
This file is deleted after read.
Thread C kworker to process post_read_wq
- rcu_do_batch
- f2fs_free_inode
- kmem_cache_free
inode is freed by rcu
- process_scheduled_works
- f2fs_late_free_dic
- f2fs_free_dic
- f2fs_release_decomp_mem
read (dic->inode)->i_compress_algorithm
This patch store compress_algorithm and sbi in dic to avoid inode UAF.
In addition, the previous solution is deprecated in [1] may cause system hang.
[1] https://lore.kernel.org/all/c36ab955-c8db-4a8b-a9d0-f07b5f426c3f@kernel.org
References
Impacted products
{
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"fs/f2fs/compress.c",
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: compress: fix UAF of f2fs_inode_info in f2fs_free_dic\n\nThe decompress_io_ctx may be released asynchronously after\nI/O completion. If this file is deleted immediately after read,\nand the kworker of processing post_read_wq has not been executed yet\ndue to high workloads, It is possible that the inode(f2fs_inode_info)\nis evicted and freed before it is used f2fs_free_dic.\n\n The UAF case as below:\n Thread A Thread B\n - f2fs_decompress_end_io\n - f2fs_put_dic\n - queue_work\n add free_dic work to post_read_wq\n - do_unlink\n - iput\n - evict\n - call_rcu\n This file is deleted after read.\n\n Thread C kworker to process post_read_wq\n - rcu_do_batch\n - f2fs_free_inode\n - kmem_cache_free\n inode is freed by rcu\n - process_scheduled_works\n - f2fs_late_free_dic\n - f2fs_free_dic\n - f2fs_release_decomp_mem\n read (dic-\u003einode)-\u003ei_compress_algorithm\n\nThis patch store compress_algorithm and sbi in dic to avoid inode UAF.\n\nIn addition, the previous solution is deprecated in [1] may cause system hang.\n[1] https://lore.kernel.org/all/c36ab955-c8db-4a8b-a9d0-f07b5f426c3f@kernel.org"
}
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"providerMetadata": {
"dateUpdated": "2025-08-22T16:00:35.856Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
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"references": [
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"url": "https://git.kernel.org/stable/c/8fae5b6addd5f6895e03797b56e3c7b9f9cd15c9"
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{
"url": "https://git.kernel.org/stable/c/39868685c2a94a70762bc6d77dc81d781d05bff5"
}
],
"title": "f2fs: compress: fix UAF of f2fs_inode_info in f2fs_free_dic",
"x_generator": {
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"assignerShortName": "Linux",
"cveId": "CVE-2025-38627",
"datePublished": "2025-08-22T16:00:35.856Z",
"dateReserved": "2025-04-16T04:51:24.029Z",
"dateUpdated": "2025-08-22T16:00:35.856Z",
"state": "PUBLISHED"
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"nvd": "{\"cve\":{\"id\":\"CVE-2025-38627\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-08-22T16:15:36.337\",\"lastModified\":\"2025-08-22T18:08:51.663\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nf2fs: compress: fix UAF of f2fs_inode_info in f2fs_free_dic\\n\\nThe decompress_io_ctx may be released asynchronously after\\nI/O completion. If this file is deleted immediately after read,\\nand the kworker of processing post_read_wq has not been executed yet\\ndue to high workloads, It is possible that the inode(f2fs_inode_info)\\nis evicted and freed before it is used f2fs_free_dic.\\n\\n The UAF case as below:\\n Thread A Thread B\\n - f2fs_decompress_end_io\\n - f2fs_put_dic\\n - queue_work\\n add free_dic work to post_read_wq\\n - do_unlink\\n - iput\\n - evict\\n - call_rcu\\n This file is deleted after read.\\n\\n Thread C kworker to process post_read_wq\\n - rcu_do_batch\\n - f2fs_free_inode\\n - kmem_cache_free\\n inode is freed by rcu\\n - process_scheduled_works\\n - f2fs_late_free_dic\\n - f2fs_free_dic\\n - f2fs_release_decomp_mem\\n read (dic-\u003einode)-\u003ei_compress_algorithm\\n\\nThis patch store compress_algorithm and sbi in dic to avoid inode UAF.\\n\\nIn addition, the previous solution is deprecated in [1] may cause system hang.\\n[1] https://lore.kernel.org/all/c36ab955-c8db-4a8b-a9d0-f07b5f426c3f@kernel.org\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/39868685c2a94a70762bc6d77dc81d781d05bff5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/8fae5b6addd5f6895e03797b56e3c7b9f9cd15c9\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
}
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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