# CVE-2020-29661: Use after free in n/a > A use-after-free vulnerability in the Linux kernel tty subsystem allows local attackers to execute arbitrary code or escalate privileges. - **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **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-175451802, ASB-A-175451802, DEBIAN-CVE-2020-29661, GHSA-p865-45gc-8x47, RHSA-2021:0940, RHSA-2021:1031, UBUNTU-CVE-2020-29661 ## What is CVE-2020-29661? CVE-2020-29661 is a high-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 issue was discovered in the tty subsystem of the Linux kernel through 5.9.13. drivers/tty/tty_jobctrl.c allows a use-after-free attack against TIOCSPGRP, aka CID-54ffccbf053b. Weakness: CWE-667 (Improper Locking), CWE-416 (Use After Free) ## Which versions are affected by CVE-2020-29661? It affects 12 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `kpatch-patch-3_10_0-957_46_1` | Red Hat:rhel_eus:7.6::server | All versions | 0:1-4.el7 | | `kpatch-patch-3_10_0-957_48_1` | Red Hat:rhel_eus:7.6::server | All versions | 0:1-4.el7 | | `kpatch-patch-3_10_0-957_54_1` | Red Hat:rhel_eus:7.6::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-957_54_1-debuginfo` | Red Hat:rhel_eus:7.6::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-957_56_1` | Red Hat:rhel_eus:7.6::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-957_56_1-debuginfo` | Red Hat:rhel_eus:7.6::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-957_58_2` | Red Hat:rhel_eus:7.6::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-957_58_2-debuginfo` | Red Hat:rhel_eus:7.6::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-957_61_1` | Red Hat:rhel_eus:7.6::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-957_61_1-debuginfo` | Red Hat:rhel_eus:7.6::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-957_61_2` | Red Hat:rhel_eus:7.6::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-957_61_2-debuginfo` | Red Hat:rhel_eus:7.6::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-957_62_1` | Red Hat:rhel_eus:7.6::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-957_62_1-debuginfo` | Red Hat:rhel_eus:7.6::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-957_65_1` | Red Hat:rhel_eus:7.6::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-957_65_1-debuginfo` | Red Hat:rhel_eus:7.6::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-957_66_1` | Red Hat:rhel_eus:7.6::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-957_66_1-debuginfo` | Red Hat:rhel_eus:7.6::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-1062_21_1` | Red Hat:rhel_eus:7.7::server | All versions | 0:1-3.el7 | | `kpatch-patch-3_10_0-1062_21_1-debuginfo` | Red Hat:rhel_eus:7.7::server | All versions | 0:1-3.el7 | | `kpatch-patch-3_10_0-1062_26_1` | Red Hat:rhel_eus:7.7::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-1062_26_1-debuginfo` | Red Hat:rhel_eus:7.7::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-1062_30_1` | Red Hat:rhel_eus:7.7::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-1062_30_1-debuginfo` | Red Hat:rhel_eus:7.7::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-1062_31_2` | Red Hat:rhel_eus:7.7::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-1062_31_2-debuginfo` | Red Hat:rhel_eus:7.7::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-1062_31_3` | Red Hat:rhel_eus:7.7::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-1062_31_3-debuginfo` | Red Hat:rhel_eus:7.7::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-1062_33_1` | Red Hat:rhel_eus:7.7::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-1062_33_1-debuginfo` | Red Hat:rhel_eus:7.7::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-1062_36_1` | Red Hat:rhel_eus:7.7::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-1062_36_1-debuginfo` | Red Hat:rhel_eus:7.7::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-1062_37_1` | Red Hat:rhel_eus:7.7::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-1062_37_1-debuginfo` | Red Hat:rhel_eus:7.7::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-1062_40_1` | Red Hat:rhel_eus:7.7::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-1062_40_1-debuginfo` | Red Hat:rhel_eus:7.7::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-1062_43_1` | Red Hat:rhel_eus:7.7::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-1062_43_1-debuginfo` | Red Hat:rhel_eus:7.7::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-1062_45_1` | Red Hat:rhel_eus:7.7::server | All versions | 0:1-1.el7 | | `kpatch-patch-3_10_0-1062_45_1-debuginfo` | Red Hat:rhel_eus:7.7::server | All versions | 0:1-1.el7 | 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, Oracle Tekelec Platform Distribution. ## How do I fix CVE-2020-29661? Apply the vendor's patch. ## Is CVE-2020-29661 being exploited? There is no known exploitation of CVE-2020-29661 in the wild and no public exploit code. Public exploit code: - https://github.com/wojkos9/arm-CVE-2020-29661 (github_poc): https://github.com/wojkos9/arm-CVE-2020-29661 ## 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-2020-29661 and fix it if it is affected. What it is: CVE-2020-29661 is a high-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-2020-29661 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-2020-29661/ (Markdown: https://insights.sbomify.com/CVE-2020-29661/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2020-29661 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-29661 - OSV: https://osv.dev/vulnerability/CVE-2020-29661 --- From sbomify Insights: https://insights.sbomify.com/CVE-2020-29661/ Summaries are generated and may contain mistakes; the official description above is the record.