What’s Vulnerable › Vulnerabilities

CVE-2020-29661

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-12-09 · updated 2026-06-17
• Weakness: CWE-416

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.

Affected products

• Brocade Fabric OS: all versions
• Debian Linux: 9.0, 10.0
• Fedoraproject Fedora: 32, 33
• Linux kernel: from 2.6.26 before 4.4.248; from 4.5 before 4.9.248; from 4.10 before 4.14.212; from 4.15 before 4.19.163; from 4.20 before 5.4.83; from 5.5 before 5.9.14 — fixed in 4.14.212, 4.19.163, 4.4.248, 4.9.248, 5.4.83, 5.9.14
• NetApp 8300 Firmware: all versions
• NetApp 8700 Firmware: all versions
• NetApp A400 Firmware: all versions
• NetApp A700S Firmware: all versions
• Active IQ Unified Manager for VMware vSphere, Linux, and Microsoft Windows: all versions
• NetApp H410C Firmware: all versions
• NetApp Solidfire Baseboard Management Controller Firmware: all versions
• Oracle Tekelec Platform Distribution: from 7.4.0 through 7.7.1

How to fix

Upgrade to a fixed version: Linux kernel 4.14.212, 4.19.163, 4.4.248, 4.9.248. Check the vendor advisory for mitigations.

References

• http://packetstormsecurity.com/files/160681/Linux-TIOCSPGRP-Broken-Locking.html
• http://packetstormsecurity.com/files/164950/Kernel-Live-Patch-Security-Notice-LSN-0082-1.html
• http://www.openwall.com/lists/oss-security/2020/12/10/1
• https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=54ffccbf053b5b6ca4f6e45094b942fab92a25fc
• https://lists.debian.org/debian-lts-announce/2021/02/msg00018.html
• https://lists.debian.org/debian-lts-announce/2021/03/msg00010.html
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BOB25SU6XUL4TNP7KB63WNZSYTIYFDPP/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MZ7OAKAEFAXQRGBZK4LYUWINCD3D2XCL/
• https://security.netapp.com/advisory/ntap-20210122-0001/
• https://www.debian.org/security/2021/dsa-4843
• https://www.oracle.com/security-alerts/cpuoct2021.html
• http://packetstormsecurity.com/files/160681/Linux-TIOCSPGRP-Broken-Locking.html

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