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CVE-2026-99115

UnknownEPSS 0.17%

Last modified

CVE-2026-99115 is a vulnerability of currently unknown severity. In the Linux kernel, the following vulnerability has been resolved: ksmbd: fill in FileSysIdentifier in FS_POSIX_INFORMATION smb2_get_info_filesystem() reports 56 bytes for FS_POSIX_INFORMATION, that is the whole of FILE_SYSTEM_POSIX_INFO, but never assigns FileSysIdentifier. Those eight bytes go to the client as they are found in the response buffer. The buffer is zeroed on allocation, so a standalone request leaks nothing. EPSS estimates a 0.17% chance of exploitation in the next 30 days.

Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fill in FileSysIdentifier in FS_POSIX_INFORMATION smb2_get_info_filesystem() reports 56 bytes for FS_POSIX_INFORMATION, that is the whole of FILE_SYSTEM_POSIX_INFO, but never assigns FileSysIdentifier. Those eight bytes go to the client as they are found in the response buffer. The buffer is zeroed on allocation, so a standalone request leaks nothing. A compound request can leak: the offset of the next response is advanced by the length pinned for the previous one, so a reply that was written into the buffer and then dropped in favour of the short error response of smb2_set_err_rsp() stays there, and the next reply is laid over it with only the header cleared. Report the file system id statfs() returned, which is what the field is for. FileSysIdentifier is __le64 and f_fsid is a pair of ints, so assemble the value first, val[0] as the low half, and convert it on the way out.

Metrics

EPSS Probability
0.17%

5.9th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, < cb9fbcaf1f3351bea771eec557fc6c4d2f35762b; >= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, < 1d644ab9eac767d52c9b8dc0eb68c0085994d9b6; >= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, < da2ec27fdd7effbe4c94ec15b6c6a281800c5123; >= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, < f5c50f69a70fe22c44a50c869c8cd65fc35a0686; >= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, < beba2ef6f66a71f20531ac70a1acb0b221e362e9; >= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, < ab057f271ef60ff8163818badc3de75c480eca07; >= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, < db2267b27c054a6c2151ff7fbb67927e784f31d6
LinuxLinux5.15

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-99115?
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fill in FileSysIdentifier in FS_POSIX_INFORMATION smb2_get_info_filesystem() reports 56 bytes for FS_POSIX_INFORMATION, that is the whole of FILE_SYSTEM_POSIX_INFO, but never assigns FileSysIdentifier. Those eight bytes go to the client as they are found in the response buffer. The buffer is zeroed on allocation, so a standalone request leaks nothing. A compound request can leak: the offset of the next response is advanced by the length pinned for the previous one, so a reply that was written into the buffer and then dropped in favour of the short error response of smb2_set_err_rsp() stays there, and the next reply is laid over it with only the header cleared. Report the file system id statfs() returned, which is what the field is for. FileSysIdentifier is __le64 and f_fsid is a pair of ints, so assemble the value first, val[0] as the low half, and convert it on the way out.
How severe is CVE-2026-99115?
Severity scoring for CVE-2026-99115 is pending analysis. The EPSS model estimates a 0.17% probability of exploitation in the next 30 days.
How do I fix CVE-2026-99115?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST