CVE-2026-63817
f2fs: validate compress cache inode only when enabled
Description
In the Linux kernel, the following vulnerability has been resolved: f2fs: validate compress cache inode only when enabled F2FS_COMPRESS_INO() uses NM_I(sbi)->max_nid as the synthetic inode number for the compressed page cache inode. That inode only exists when the compress_cache mount option is enabled. When compress_cache is disabled, max_nid is outside the valid inode range. A corrupted directory entry that points to ino == max_nid should therefore be rejected by f2fs_check_nid_range(). However, is_meta_ino() currently treats F2FS_COMPRESS_INO() as a meta inode unconditionally, so f2fs_iget() bypasses do_read_inode() and its nid range check, and instantiates a fake internal inode instead. Gate the compressed cache inode case on COMPRESS_CACHE, matching f2fs_init_compress_inode(). With compress_cache disabled, ino == max_nid now follows the normal inode path and is rejected as an out-of-range nid.
INFO
Published Date :
July 19, 2026, 12:16 p.m.
Last Modified :
July 19, 2026, 12:16 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Products
The following products are affected by CVE-2026-63817
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
Solution
- Update the Linux kernel to the patched version.
- Ensure compress_cache mount option is configured correctly.
- Reboot the system after updating.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-63817.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-63817 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-63817
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-63817 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-63817 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jul. 19, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6ce19aff0b8cd386860855185c6cd79337fc4d2b', 'lessThan': '29115b8c9172d34e67ab26cc4f6c209b7a236d7a', 'versionType': 'git'}, {'status': 'affected', 'version': '6ce19aff0b8cd386860855185c6cd79337fc4d2b', 'lessThan': '13e4b59d3a9413f66f116fa6c4828519b960a5ea', 'versionType': 'git'}, {'status': 'affected', 'version': '6ce19aff0b8cd386860855185c6cd79337fc4d2b', 'lessThan': '16161444c30d8dff9428abbae42b72ce4e32a932', 'versionType': 'git'}, {'status': 'affected', 'version': '6ce19aff0b8cd386860855185c6cd79337fc4d2b', 'lessThan': '77f216ff9ce5cde8eed9f6d12707e906dffdc9f7', 'versionType': 'git'}, {'status': 'affected', 'version': '6ce19aff0b8cd386860855185c6cd79337fc4d2b', 'lessThan': '0969926d987bbde9a1aa49da317582ba37095805', 'versionType': 'git'}, {'status': 'affected', 'version': '6ce19aff0b8cd386860855185c6cd79337fc4d2b', 'lessThan': '5073c66a96a9c23c0c2533ed4ed06e42f9021208', 'versionType': 'git'}, {'status': 'affected', 'version': 'a23706426da9b611be5beae0f3faa260fb453b4e', 'versionType': 'git'}, {'status': 'affected', 'version': '5.13.19', 'lessThan': '5.14', 'versionType': 'semver'}], 'programFiles': ['fs/f2fs/inode.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '5.14'}, {'status': 'unaffected', 'version': '0', 'lessThan': '5.14', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.1.177', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.144', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.95', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.38', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.3', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/f2fs/inode.c'], 'defaultStatus': 'affected'}] Added Description In the Linux kernel, the following vulnerability has been resolved: f2fs: validate compress cache inode only when enabled F2FS_COMPRESS_INO() uses NM_I(sbi)->max_nid as the synthetic inode number for the compressed page cache inode. That inode only exists when the compress_cache mount option is enabled. When compress_cache is disabled, max_nid is outside the valid inode range. A corrupted directory entry that points to ino == max_nid should therefore be rejected by f2fs_check_nid_range(). However, is_meta_ino() currently treats F2FS_COMPRESS_INO() as a meta inode unconditionally, so f2fs_iget() bypasses do_read_inode() and its nid range check, and instantiates a fake internal inode instead. Gate the compressed cache inode case on COMPRESS_CACHE, matching f2fs_init_compress_inode(). With compress_cache disabled, ino == max_nid now follows the normal inode path and is rejected as an out-of-range nid. Added Reference https://git.kernel.org/stable/c/0969926d987bbde9a1aa49da317582ba37095805 Added Reference https://git.kernel.org/stable/c/13e4b59d3a9413f66f116fa6c4828519b960a5ea Added Reference https://git.kernel.org/stable/c/16161444c30d8dff9428abbae42b72ce4e32a932 Added Reference https://git.kernel.org/stable/c/29115b8c9172d34e67ab26cc4f6c209b7a236d7a Added Reference https://git.kernel.org/stable/c/5073c66a96a9c23c0c2533ed4ed06e42f9021208 Added Reference https://git.kernel.org/stable/c/77f216ff9ce5cde8eed9f6d12707e906dffdc9f7