CVE-2026-64257
published 2026-07-25CVE-2026-64257: In the Linux kernel, the following vulnerability has been resolved: smb: client: reject overlapping data areas in SMB2 responses Commit 53b7c271f06b ("smb…
PriorityP348critical9.1CVSS 3.1
AVNACLPRNUINSUCHINAH
EPSS
0.70%
52.0th percentile
In the Linux kernel, the following vulnerability has been resolved:
smb: client: reject overlapping data areas in SMB2 responses
Commit 53b7c271f06b ("smb: client: restrict implied bcc[0] exemption to
responses without data area") restricted the implied bcc[0] length
exception to responses without a data area. However, the overlap
handling in __smb2_calc_size() clears data_length, which can make an
invalid response appear to have no data area and so qualify for the
exception.
Track data area overlap separately and reject such responses before
applying the length compatibility exceptions.
Affected
13 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| linux | linux | — | — |
| linux | linux | — | — |
| linux | linux | >= 31c6312608c60b72a1feb99a5afb680645a3e8a3 < 445ece263131780dee273d727a4d6f11934feec7 | 445ece263131780dee273d727a4d6f11934feec7 |
| linux | linux | >= 419ec1b604d7fb60c10aec2dc062371f9fcd4940 < 4a9d2657d3e05f6ed09c148cb127b4e58702275f | 4a9d2657d3e05f6ed09c148cb127b4e58702275f |
| linux | linux | >= 5.10.261 < 5.11 | 5.11 |
| linux | linux | >= 5.15.212 < 5.16 | 5.16 |
| linux | linux | >= 53b7c271f06be4dd5cfc8c6ef552a8355c891a7f < 8986c932905ea508d66da421eb2eb6e676ace1fe | 8986c932905ea508d66da421eb2eb6e676ace1fe |
| linux | linux | >= 573e502d14714d2947e22e7eff40ec20a6a44a42 < 36bfa52459e45c0d5b668de2f1c91f6dc5c67775 | 36bfa52459e45c0d5b668de2f1c91f6dc5c67775 |
| linux | linux | >= 6e9d10f62773b99bd927940fd9cbdfe7207e23ff < 57cba95f0e97c6f6e45e6731da30aff091bd7460 | 57cba95f0e97c6f6e45e6731da30aff091bd7460 |
| linux | linux | >= ceb875a375dedbf51c9425c1d13a2d7a8435c08c < fdafa1e68dc75045b7b617e6e7d2854950804d83 | fdafa1e68dc75045b7b617e6e7d2854950804d83 |
| linux | linux_kernel | — | — |
| linux | linux_kernel | >= 5.10.261 < 5.11 | 5.11 |
| linux | linux_kernel | >= 5.15.212 < 5.16 | 5.16 |
CVSS provenance
nvdv3.19.1CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
vendor_redhat9.1CRITICAL
Stop checking back — get the weekly exploitation signal.
Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.
Red Hat
kernel: smb: client: reject overlapping data areas in SMB2 responses
vendor_redhat·2026-07-25·CVSS 9.1
CVE-2026-64257 [CRITICAL] CWE-130 kernel: smb: client: reject overlapping data areas in SMB2 responses
kernel: smb: client: reject overlapping data areas in SMB2 responses
A flaw was found in the Linux kernel's Server Message Block (SMB) client. A remote attacker could exploit a vulnerability where the client improperly handles SMB2 responses containing overlapping data areas. This incorrect processing of malformed network data could lead to a denial of service (DoS) or other severe system impact, compromising the availability and potentially the confidentiality of the affected system.
Package: kernel (Red Hat Enterprise Linux 10) - Not affected
Package: kernel (Red Hat Enterprise Linux 6) - Not affected
Package: kernel (Red Hat Enterprise Linux 7) - Not affected
Package: kernel-rt (Red Hat Enterprise Linux 7) - Not affected
Package: kernel (Red Hat Enterprise Linux 8) - Not affected
GHSA
In the Linux kernel, the following vulnerability has been resolved: smb: client: reject overlapping data areas in SMB2 responses Commit 53b7c271f06b ("smb: client: restrict implied bcc[0] exemption
ghsa_unreviewed·2026-07-25
CVE-2026-64257 In the Linux kernel, the following vulnerability has been resolved: smb: client: reject overlapping data areas in SMB2 responses Commit 53b7c271f06b ("smb: client: restrict implied bcc[0] exemption
In the Linux kernel, the following vulnerability has been resolved:
smb: client: reject overlapping data areas in SMB2 responses
Commit 53b7c271f06b ("smb: client: restrict implied bcc[0] exemption to
responses without data area") restricted the implied bcc[0] length
exception to responses without a data area. However, the overlap
handling in __smb2_calc_size() clears data_length, which can make an
invalid response appear to have no data area and so qualify for the
exception.
Track data area overlap separately and reject such responses before
applying the length compatibility exceptions.
No detection rules found.
No public exploits indexed.
https://git.kernel.org/stable/c/36bfa52459e45c0d5b668de2f1c91f6dc5c67775https://git.kernel.org/stable/c/445ece263131780dee273d727a4d6f11934feec7https://git.kernel.org/stable/c/4a9d2657d3e05f6ed09c148cb127b4e58702275fhttps://git.kernel.org/stable/c/57cba95f0e97c6f6e45e6731da30aff091bd7460https://git.kernel.org/stable/c/8986c932905ea508d66da421eb2eb6e676ace1fehttps://git.kernel.org/stable/c/fdafa1e68dc75045b7b617e6e7d2854950804d83
2026-07-25
Published