CVE-2026-43362

smb: client: fix in-place encryption corruption in SMB2_write()

HIGH
8.1
CVSS Score
Published: May 8, 2026 at 02:21 PM UTC
Updated: October 19, 2026 at 08:18 PM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
HIGH8.1
Exploit prediction
EPSS 0.3%
SSVC
No known exploit

Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix in-place encryption corruption in SMB2_write() SMB2_write() places write payload in iov[1..n] as part of rq_iov. smb3_init_transform_rq() pointer-shares rq_iov, so crypt_message() encrypts iov[1] in-place, replacing the original plaintext with ciphertext. On a replayable error, the retry sends the same iov[1] which now contains ciphertext instead of the original data, resulting in corruption. The corruption is most likely to be observed when connections are unstable, as reconnects trigger write retries that re-send the already-encrypted data. This affects SFU mknod, MF symlinks, etc. On kernels before 6.10 (prior to the netfs conversion), sync writes also used this path and were similarly affected. The async write path wasn't unaffected as it uses rq_iter which gets deep-copied. Fix by moving the write payload into rq_iter via iov_iter_kvec(), so smb3_init_transform_rq() deep-copies it before encryption.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

4.11 ≤ v < 6.6.1306.13 ≤ v < 6.18.196.19 ≤ v < 6.19.96.7 ≤ v < 6.12.7826e93dc0a3eefb0be60bcb9ecd8d7a7fd5c3984.117.07.0 rc17.0 rc27.0 rc3
Vendor states this is fixed in 438e77435aee2894d5edf90be5c87004a57f6258 (fixed)
Vendor states this is fixed in 52327268224fb9ccc7ecfbbdfdfff54b6e93c518 (fixed)
Vendor states this is fixed in 92e64f1852f455f57d0850989e57c30d7fac7d95 (fixed)
Vendor states this is fixed in aea5e37388a080361110ab5790f57ae0af383650 (fixed)
Vendor states this is fixed in d78840a6a38d312dc1a51a65317bb67e46f0b929 (fixed)
Vendor states this is fixed in 4.11 (unaffected)
Vendor states this is fixed in 6.12.78 (unaffected)
Vendor states this is fixed in 6.18.19 (unaffected)
Vendor states this is fixed in 6.19.9 (unaffected)
Vendor states this is fixed in 6.6.130 (unaffected)
Vendor states this is fixed in 7.0 (unaffected)

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.1HIGHLinux
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-787CWE-662

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