VulnerabilityPublished 28 Oct 2026

CVE-2026-99137: Linux kernel · cifs: don't update i_size in cifs_do_truncate without a cached handle

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in fe39cd9d48f2346605f3746e0cc19e89d5f373eb : update Linux kernel when convenient.

Data as of 28 Oct 2026, 10:58 UTC

Severity

Unrated

Rated by Threat Radar · CVSS not yet scored by NVD

Patch: Available – fixed in fe39cd9d48f2346605f3746e0cc19e89d5f373eb, 88a51743cd8094b76fd910f53f718747c7729cc8, 04d020b3d0b58a1b7e116900e4095b96a7f4e11a

Exploitation evidence

Disclosed: evidence found.
CVE published 28 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Linux kernel to fe39cd9d48f2346605f3746e0cc19e89d5f373eb, 88a51743cd8094b76fd910f53f718747c7729cc8 or 04d020b3d0b58a1b7e116900e4095b96a7f4e11a.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 110fee6b9bb58a5c50047fc2594d415f741b591e, < fe39cd9d48f2346605f3746e0cc19e89d5f373eb	Fixed in fe39cd9d48f2346605f3746e0cc19e89d5f373eb
LinuxLinux	Affected ≥ 110fee6b9bb58a5c50047fc2594d415f741b591e, < 88a51743cd8094b76fd910f53f718747c7729cc8	Fixed in 88a51743cd8094b76fd910f53f718747c7729cc8
LinuxLinux	Affected ≥ 110fee6b9bb58a5c50047fc2594d415f741b591e, < 04d020b3d0b58a1b7e116900e4095b96a7f4e11a	Fixed in 04d020b3d0b58a1b7e116900e4095b96a7f4e11a
LinuxLinux	Affected =6.18	Fixed in–
Debiandebian/linux`pkg:deb/debian/linux`Other threats	Affected =6.18	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

In the Linux kernel, the following vulnerability has been resolved: cifs: don't update i_size in cifs_do_truncate without a cached handle If find_writable_file() returns null, cifs_file_flush will return 0 without issuing set_file_size, and the outer 'if (!rc)' block will set i_size to 0 before telling the server to truncate. If the cifs_open() then fails, the inode will have size 0, while the server file is unchanged. Move the netfs_resize_file() and cifs_setsize() into the 'if (cfile)', so they only run after a successful set_file_size. In the no-handle else branch, evict stale pages with truncate_inode_pages before the O_TRUNC open to dispose of old cache pages, and let the open response set the i_size.

References

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