CVE-2026-43362: Linux kernel · smb: client: fix in-place encryption corruption in SMB2_write()
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 8.1 High · fixed in d78840a6a38d312dc1a51a65317bb67e46f0b929 : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:18 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 17% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Limited control over the software or limited information exposure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in d78840a6a38d312dc1a51a65317bb67e46f0b929, aea5e37388a080361110ab5790f57ae0af383650, 52327268224fb9ccc7ecfbbdfdfff54b6e93c518 +2
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 8 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in– |
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.
References
- git.kernel.org/stable/c/438e77435aee2894d5edf90be5c87004a57f6258 (opens in a new tab)
- git.kernel.org/stable/c/52327268224fb9ccc7ecfbbdfdfff54b6e93c518 (opens in a new tab)
- git.kernel.org/stable/c/92e64f1852f455f57d0850989e57c30d7fac7d95 (opens in a new tab)
- git.kernel.org/stable/c/aea5e37388a080361110ab5790f57ae0af383650 (opens in a new tab)
- git.kernel.org/stable/c/d78840a6a38d312dc1a51a65317bb67e46f0b929 (opens in a new tab)