# 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.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H`)
- **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:** Yes
- **Published:** 8 May 2026
- **Updated:** 19 Oct 2026
- **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, ROOT-OS-UBUNTU-2404-CVE-2026-43362, UBUNTU-CVE-2026-43362

## 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.

Weakness: CWE-787 (Out-of-bounds Write), CWE-662 (Improper Synchronization)

## Which versions are affected by CVE-2026-43362?

It affects 1 product.


Products: 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

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-43362 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-43362 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-43362/ (Markdown: https://insights.sbomify.com/CVE-2026-43362/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43362
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43362
- OSV: https://osv.dev/vulnerability/CVE-2026-43362

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43362/
Summaries are generated and may contain mistakes; the official description above is the record.