CVE-2026-43362
smb: client: fix in-place encryption corruption in SMB2_write()
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.
INFO
Published Date :
May 8, 2026, 3:16 p.m.
Last Modified :
May 8, 2026, 3:16 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Update the Linux kernel to a version with the fix.
- Ensure the SMB3 encryption is properly configured.
- Test connections for stability and data integrity.
References to Advisories, Solutions, and Tools
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CVE-2026-43362.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-43362 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-43362
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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CVE-2026-43362 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-43362 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 08, 2026
Action Type Old Value New Value Added 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. Added Reference https://git.kernel.org/stable/c/438e77435aee2894d5edf90be5c87004a57f6258 Added Reference https://git.kernel.org/stable/c/52327268224fb9ccc7ecfbbdfdfff54b6e93c518 Added Reference https://git.kernel.org/stable/c/92e64f1852f455f57d0850989e57c30d7fac7d95 Added Reference https://git.kernel.org/stable/c/aea5e37388a080361110ab5790f57ae0af383650 Added Reference https://git.kernel.org/stable/c/d78840a6a38d312dc1a51a65317bb67e46f0b929