Linux Kernel n_tty_write Race Condition Local Privilege Escalation (CVE-2014-0196)
Executive & SecOps Summary
SECOPS ASSESSMENTAll Linux systems running Linux kernel versions up to and including 3.14.3
Local attackers can exploit a race condition to corrupt kernel memory, leading to a denial of service (system crash) or full root privilege escalation
Apply the latest kernel security updates provided by your OS vendor and reboot the system
Affected Products & Version Scope
Remediation & Live Workaround Commands
PATCH & WORKAROUND1. Official Patch & Version Upgrade Commands
Update your Linux kernel to the latest stable release using your distribution's package manager and reboot the system to apply changes.
# For RHEL / CentOS systems
sudo yum update -y kernel
sudo reboot
# For Ubuntu / Debian systems
sudo apt-get update && sudo apt-get install --only-upgrade -y linux-image-generic
sudo reboot2. Temporary Workaround & Hardening Configuration
If an immediate reboot or kernel update is not feasible, restrict compiler access and harden temporary directories to prevent the execution of exploit binaries.
# Restrict compiler access to root only
sudo chmod 700 /usr/bin/gcc
sudo chmod 700 /usr/bin/g++
# Remount temporary directories with noexec flag
sudo mount -o remount,noexec /tmp
sudo mount -o remount,noexec /dev/shm3. Log Audit & IoC Verification Commands
Check the current running kernel version and inspect system logs for signs of kernel panics or memory corruption related to the tty subsystem.
# Verify the current running kernel version
uname -r
# Search for tty-related kernel faults or crashes in system logs
sudo dmesg | grep -Ei 'tty|general protection fault|unable to handle kernel'
sudo grep -Ei 'tty|general protection fault' /var/log/messages /var/log/syslog 2>/dev/nullBlock Kernel Privilege Escalation & Ransomware Payloads Before You Can Reboot
Protect unpatched Windows, Linux, and macOS workloads against in-memory exploitation and lateral movement with autonomous EDR.
Technical Root Cause & Exploitation Mechanics
1. Vulnerability Overview & Root Cause
This vulnerability is a race condition found in the pseudo-terminal (tty) subsystem of the Linux kernel, specifically within drivers/tty/n_tty.c. The root cause lies in the n_tty_write function, which fails to properly synchronize access to the tty driver buffer when the 'LECHO' flag is enabled and the 'OPOST' flag is disabled ('LECHO & !OPOST'). This lack of proper locking allows concurrent read and write operations to corrupt kernel memory.
2. Exploitation Mechanics & Attack Scenario
A local attacker with basic shell access can execute a multi-threaded exploit that performs rapid, concurrent write and read operations with long strings on a tty device. Due to the race condition, the kernel's buffer boundary checks are bypassed between the time-of-check and time-of-use (TOCTOU). This leads to an out-of-bounds write, corrupting the kernel slab allocator memory. By carefully structuring the corrupted memory, the attacker can hijack kernel control flow to execute arbitrary code with root privileges.
3. Infrastructure & Business Impact
As a vulnerability listed in the CISA KEV catalog, this flaw has been actively exploited in the wild. In multi-tenant environments, cloud infrastructures, or shared hosting servers, this vulnerability poses a severe threat as it allows any low-privileged user or compromised application container to escape boundaries and gain full administrative control over the host operating system.
Official Vendor Advisories & References
The n_tty_write function in drivers/tty/n_tty.c in the Linux kernel through 3.14.3 does not properly manage tty driver access in the "LECHO & !OPOST" case, which allows local users to cause a denial of service (memory corruption and system crash) or gain privileges by triggering a race condition involving read and write operations with long strings.
Frequently Asked SecOps Questions (CVE-2014-0196)
FAQQ1. How critical is CVE-2014-0196 and is it actively exploited in the wild?
CVE-2014-0196 is rated CVSS 5.5 (MEDIUM) with a 30-day EPSS exploitation probability of 20.3%. It is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, requiring immediate emergency remediation.
Q2. Which vendors and products are affected by CVE-2014-0196?
Primary impacted vendors include linux across linux_kernel. Scope summary: Linux kernel versions up to and including 3.14.3 (Affects major distributions including RHEL, CentOS, Debian, Ubuntu, and SUSE)
Q3. What temporary mitigations or workarounds exist for CVE-2014-0196 before patching?
[Mitigation] Apply the latest kernel security updates provided by your OS vendor and reboot the system Follow the CLI remediation commands and interactive SecOps checklist on this page to restrict exposure prior to your maintenance window.
Generate an Internal Engineering Notice or CISO Report for CVE-2014-0196
Instantly format this advisory into an executive CISO summary or engineering patch ticket.
🔗 Related Advisories in Similar Stack (linux)
View Category →Linux Kernel IPv6 Socket Memory Corruption Vulnerability (CVE-2026-53362) Analysis and Mitigation Guide
[Affected Scope] Linux kernel systems utilizing UDPv6 sockets with MSG_MORE and MSG_SPLICE_PAGES flags
Linux Kernel algif_aead In-place Operation Vulnerability Leading to Local Privilege Escalation (CVE-2026-31431)
[Affected Scope] Systems running Linux kernel with the `algif_aead` crypto subsystem module enabled.
Linux Kernel Netfilter Bridge ebt_snat ARP Rewrite Vulnerability (CVE-2026-53266)
[Affected Scope] Linux systems utilizing ebtables SNAT targets within bridge netfilter configurations.
Linux Kernel Memory Corruption via Missing Shared-Frag Marker in skbuff (CVE-2026-46300)
[Affected Scope] Linux kernel network stack (skbuff) and systems utilizing IPsec (ESP).
Subscribe to Daily Vulnerability Briefings & KEV Alerts
Concise morning briefings for SecOps, DevSecOps, and SRE teams covering newly exploited CVEs and mitigation priorities.