Critical severity · published May 1, 2026
CVE-2026-31705
ksmbd: fix out-of-bounds write in smb2_get_ea() EA alignment
9.8
CVSS
0.4%
EPSS
No
On KEV
Description
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix out-of-bounds write in smb2_get_ea() EA alignment
smb2_get_ea() applies 4-byte alignment padding via memset() after
writing each EA entry. The bounds check on buf_free_len is performed
before the value memcpy, but the alignment memset fires unconditionally
afterward with no check on remaining space.
When the EA value exactly fills the remaining buffer (buf_free_len == 0
after value subtraction), the alignment memset writes 1-3 NUL bytes
past the buf_free_len boundary. In compound requests where the response
buffer is shared across commands, the first command (e.g., READ) can
consume most of the buffer, leaving a tight remainder for the QUERY_INFO
EA response. The alignment memset then overwrites past the physical
kvmalloc allocation into adjacent kernel heap memory.
Add a bounds check before the alignment memset to ensure buf_free_len
can accommodate the padding bytes.
This is the same bug pattern fixed by commit beef2634f81f ("ksmbd: fix
potencial OOB in get_file_all_info() for compound requests") and
commit fda9522ed6af ("ksmbd: fix OOB write in QUERY_INFO for compound
requests"), both of which added bounds checks before unconditional
writes in QUERY_INFO response handlers.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 34% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
KE
Kernel · Linux
5.15.145 before 5.16; 6.1.71 before 6.2; 6.6 before 6.6.136; 6.7 before 6.12.84; 6.13 before 6.18.25; 6.19 before 7.0.2 · source: NVD
LI
Linux · Linux
9f297df20d93411c0b4ddad7f88ba04a7cd36e77 before ddbbc8b2a09dd2cfed90871313e3691ae1db08a2; e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d before ffbce350c6fd1e99116ea57383b9031717e36d3b; e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d before 98f3de6ef4efbd899348d333f0902dc4ff14380c; e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d before 790304c02bf9bd7b8171feda4294d6e62d32ae8f; e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d before 922d48fe8c19f388ffa2f709f33acaae4e408de2; e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d before 30010c952077a1c89ecdd71fc4d574c75a8f5617; +4 more · source: vendor
SS
SIMATIC S7-1500 TM MFP - GNU/Linux subsystem · Siemens
0 · source: CISA
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-31705
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-31705
Patch
https://git.kernel.org/stable/c/30010c952077a1c89ecdd71fc4d574c75a8f5617
Patch
https://git.kernel.org/stable/c/790304c02bf9bd7b8171feda4294d6e62d32ae8f
Patch
https://git.kernel.org/stable/c/922d48fe8c19f388ffa2f709f33acaae4e408de2
Patch
https://git.kernel.org/stable/c/98f3de6ef4efbd899348d333f0902dc4ff14380c
git.kernel.org
https://git.kernel.org/stable/c/ddbbc8b2a09dd2cfed90871313e3691ae1db08a2
Patch
https://git.kernel.org/stable/c/ffbce350c6fd1e99116ea57383b9031717e36d3b
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