UBUNTU-CVE-2026-53174
In the Linux kernel, the following vulnerability has been resolved: ovl: keep err zero after successful ovl_cache_get() ovl_iterate_merged() stores PTR_ERR(cache) in err before checking IS_ERR(cache). On success err holds the truncated cache pointer and can be returned as a bogus non-zero error. The syzbot reproducer reaches this through overlay-on-overlay readdir: getdents64 iterate_dir(outer overlay file) ovl_iterate_merged() ovl_cache_get() ovl_dir_read_merged() ovl_dir_read() iterate_dir(inner overlay file) ovl_iterate_merged() Only compute PTR_ERR(cache) on the error path.
02 / AFFECTED SOFTWARE
Affected packages
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16 explicit affected versions
3 explicit affected versions
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26 explicit affected versions
45 explicit affected versions
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9 explicit affected versions
11 explicit affected versions
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1 explicit affected versions
7 explicit affected versions
13 explicit affected versions
43 explicit affected versions
10 explicit affected versions
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14 explicit affected versions
4 explicit affected versions
78 explicit affected versions
11 explicit affected versions
1 explicit affected versions
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03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
In the Linux kernel, the following vulnerability has been resolved: ovl: keep err zero after successful ovl_cache_get() ovl_iterate_merged() stores PTR_ERR(cache) in err before checking IS_ERR(cache). On success err holds the truncated cache pointer and can be returned as a bogus non-zero error. The syzbot reproducer reaches this through overlay-on-overlay readdir: getdents64 iterate_dir(outer overlay file) ovl_iterate_merged() ovl_cache_get() ovl_dir_read_merged() ovl_dir_read() iterate_dir(inner overlay file) ovl_iterate_merged() Only compute PTR_ERR(cache) on the error path.
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/1711b6ed6953cee5940ca4c3a6e77f1b3798cee2
- https://git.kernel.org/stable/c/1711b6ed6953cee5940ca4c3a6e77f1b3798cee2
- https://git.kernel.org/stable/c/e7051909a01bfb883bfa78b27514854068ac4b85
- https://ubuntu.com/security/CVE-2026-53174
- https://ubuntu.com/security/notices/USN-8489-1
- https://ubuntu.com/security/notices/USN-8566-1
- https://ubuntu.com/security/notices/USN-8569-1
- https://ubuntu.com/security/notices/USN-8593-1
- https://ubuntu.com/security/notices/USN-8603-1
- https://ubuntu.com/security/notices/USN-8618-1
- https://www.cve.org/CVERecord?id=CVE-2026-53174