A critical vulnerability, identified as CVE-2025-21700, has been discovered in the Linux kernel. This vulnerability allows for privilege escalation due to a use-after-free (UAF) condition in the networking scheduling component. The vulnerability was made public on February 13, 2025, and has been assigned a CVSS score of 7.8, indicating a high severity level that necessitates immediate attention from system administrators.
Risk to organizations includes unauthorized access and potential manipulation of system processes. Given the nature of this vulnerability, attackers may leverage the UAF condition to escalate privileges and execute arbitrary code in a privileged context. Organizations should prioritize patching immediately to mitigate the associated risks.
The vulnerability has not been found to have any known public exploits at this time, which further emphasizes the importance of proactive patch management and vulnerability remediation. With the vulnerability being classified as high severity, it is essential for organizations to take swift action to secure their systems.
The urgency for defenders is high, as failure to address this vulnerability may expose systems to significant risk. The Linux community has provided patches to resolve this issue, and it is critical for users to implement these updates without delay.
Vulnerability Details
In the Linux kernel, the following vulnerability has been resolved: net: sched: Disallow replacing of child qdisc from one parent to another. This vulnerability allows for privilege escalation through a UAF condition as demonstrated in the exploit steps provided by the researcher Lion Ackermann.
The CVSS score of 7.8 indicates that this vulnerability poses a serious threat, particularly as it has a high impact on confidentiality, integrity, and availability. Affected systems include all versions of the Linux kernel prior to the vendor patch.
The vulnerability was published on February 13, 2025. The CWE classification is CWE-416, which corresponds to use-after-free vulnerabilities.
Technical Analysis
The root cause of CVE-2025-21700 stems from improper handling of memory within the Linux kernel's network scheduling component. The attack vector is local, meaning that an attacker must have local access to the system to exploit the vulnerability. The attack complexity is low, and only low privileges are required to execute the attack, making it accessible to a larger pool of potential attackers.
User interaction is not required for exploitation, which increases the risk to organizations. If successfully exploited, the impacts on confidentiality, integrity, and availability are all considered high, leading to potentially severe consequences for affected systems.
Risk & Impact Analysis
Real-world deployment risk associated with this vulnerability is significant. Organizations running vulnerable versions of the Linux kernel face the potential for unauthorized access and privilege escalation. This could lead to unauthorized modifications of system settings and data exfiltration, among other malicious activities.
The blast radius includes any system that relies on the vulnerable kernel versions, thus affecting numerous environments and applications. Organizations should assess their risk posture in light of this vulnerability and prioritize remediation based on their specific deployment.
With a CVSS score of 7.8 and considering the absence of known exploits, the urgency for organizations to mitigate this vulnerability is high. Systems should be patched as soon as possible to avoid potential exploitation by malicious actors.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The following versions of the Linux kernel are affected by CVE-2025-21700: All versions prior to the vendor patch, specifically those between 2.6.12 and 5.4.291, as well as 5.5 to 5.10.235, 5.11 to 5.15.179, 5.16 to 6.1.129, 6.2 to 6.6.76, 6.7 to 6.12.13, and 6.13 to 6.13.2.
Mitigation & Remediation
To mitigate this vulnerability, organizations should ensure that they apply the latest patches provided by the Linux community. Specifically, updating to the latest stable version of the Linux kernel is essential. Organizations should validate remediation effectiveness through penetration testing to identify similar weaknesses.
In cases where immediate patching is not feasible, organizations should consider implementing workarounds such as restricting access to affected systems and monitoring logs for unusual activity. Additionally, hardening configurations to limit privileges for users and services can help mitigate risks while a patch is being applied.
Regular monitoring and review of security practices should be conducted to ensure the integrity and security of the systems.
Detection Guidance
Organizations should monitor logs for indicators of exploitation attempts, including unusual network traffic patterns and unauthorized access attempts. Behavioral anomalies such as unexpected changes in system performance or configuration should also be logged.
Maintaining updated signatures for intrusion detection systems (IDS) can help identify and alert on potential exploitation of this vulnerability.
AppSecure Threat Intelligence Insight
CVE-2025-21700 highlights a significant trend in the exploitation of privilege escalation vulnerabilities within network components. The long-term significance of this vulnerability underscores the necessity for organizations to adopt a proactive security stance, including regular updates and rigorous testing of network configurations.
This case serves as a reminder of the importance of collaborative efforts in vulnerability disclosure and remediation. Security teams should consider establishing a penetration testing methodology to address such vulnerabilities systematically.
By investing in continuous security practices and learning from past vulnerabilities, organizations can enhance their resilience against emerging threats and reduce the likelihood of successful attacks.
For additional insights, organizations are encouraged to explore our resources on security testing best practices and tools.
security testing best practices and tools to stay informed.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
.webp)