# CVE-2020-29660: Use after free in n/a

> A locking inconsistency in the Linux kernel tty subsystem allows a read-after-free attack, potentially enabling code execution or privilege escalation.

- **Severity:** Medium 4.4 (`CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 9 Dec 2020
- **Updated:** 4 Aug 2024
- **Also known as:** A-175451844, ASB-A-175451844, DEBIAN-CVE-2020-29660, GHSA-6v44-4w2g-hxp9, UBUNTU-CVE-2020-29660

## What is CVE-2020-29660?

CVE-2020-29660 is a medium-severity use after free vulnerability in Broadcom Fabric Operating System, published on 9 Dec 2020. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A locking inconsistency issue was discovered in the tty subsystem of the Linux kernel through 5.9.13. drivers/tty/tty_io.c and drivers/tty/tty_jobctrl.c may allow a read-after-free attack against TIOCGSID, aka CID-c8bcd9c5be24.

Weakness: CWE-667 (Improper Locking), CWE-416 (Use After Free)

## Which versions are affected by CVE-2020-29660?

It affects 11 products.


Products: Broadcom Fabric Operating System, Debian Debian Linux, Fedoraproject Fedora, Linux kernel, Netapp 8300 Firmware, Netapp 8700 Firmware, Netapp A400 Firmware, Netapp A700s Firmware, Netapp Active Iq Unified Manager, Netapp H410c Firmware, Netapp Solidfire Baseboard Management Controller Firmware.

## How do I fix CVE-2020-29660?

Apply the vendor's patch.

## Is CVE-2020-29660 being exploited?

There is no known exploitation of CVE-2020-29660 in the wild and no public exploit code.

## Other vulnerabilities in Broadcom Fabric Operating System

- [CVE-2025-1976](https://insights.sbomify.com/CVE-2025-1976/): Broadcom Brocade Fabric OS Code Injection (high 8.6, exploited in the wild)
- [CVE-2021-22555](https://insights.sbomify.com/CVE-2021-22555/): Linux Kernel Heap Out-of-Bounds Write (high 8.3, exploited in the wild)
- [CVE-2022-33186](https://insights.sbomify.com/CVE-2022-33186/): Command injection in Brocade Fabric OS (critical 9.8)
- [CVE-2021-27797](https://insights.sbomify.com/CVE-2021-27797/): Hardcoded credentials in Brocade Fabric OS (critical 9.8)
- [CVE-2020-15371](https://insights.sbomify.com/CVE-2020-15371/): Code injection in Brocade Fabric OS (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-29660 and fix it if it is affected.

What it is: CVE-2020-29660 is a medium-severity use after free vulnerability in Broadcom Fabric Operating System, published on 9 Dec 2020. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-29660 in the wild and no public exploit code.

Affected product: Broadcom Fabric Operating System. 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-2020-29660/ (Markdown: https://insights.sbomify.com/CVE-2020-29660/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-29660
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-29660
- OSV: https://osv.dev/vulnerability/CVE-2020-29660

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-29660/
Summaries are generated and may contain mistakes; the official description above is the record.