CVE-2026-43362 smb: client: fix in-place encryption corruption in SMB2_write()
A flaw in the Linux kernel SMB client causes data corruption during write retries on unstable connections, leading to incorrect file content.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-43362?
CVE-2026-43362 is a high-severity vulnerability in Linux kernel, published on 8 May 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official 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.
Which versions are affected by CVE-2026-43362?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-43362?
Apply the vendor's patch.
Is CVE-2026-43362 being exploited?
There is no known exploitation of CVE-2026-43362 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-43362, DEBIAN-CVE-2026-43362, GHSA-3mqh-w39c-q3pj, ROOT-OS-DEBIAN-11-CVE-2026-43362, ROOT-OS-DEBIAN-12-CVE-2026-43362, ROOT-OS-UBUNTU-2204-CVE-2026-43362 and 2 more.