In the Linux kernel, the following vulnerability has been resolved: net_sched: hfsc: Fix a UAF vulnerability in class handling This patch fixes a Use-After-Free vulnerability in the HFSC qdisc class handling. The issue occurs due to a time-of-check/time-of-use condition in hfsc_change_class() when working with certain child qdiscs like netem or codel. The vulnerability works as follows: 1. hfsc_change_class() checks if a class has packets (q.qlen != 0) 2. It then calls qdisc_peek_len(), which for certain qdiscs (e.g., codel, netem) might drop packets and empty the queue 3. The code continues assuming the queue is still non-empty, adding the class to vttree 4. This breaks HFSC scheduler assumptions that only non-empty classes are in vttree 5. Later, when the class is destroyed, this can lead to a Use-After-Free The fix adds a second queue length check after qdisc_peek_len() to verify the queue wasn't emptied.
This vulnerability carries a HIGH severity rating with a CVSS v3.1 score of 7.8, requiring local system access to exploit with relatively low complexity without requiring user interaction requiring only low-level privileges . The vulnerability impacts confidentiality (data exposure), integrity (unauthorized modifications), and availability (service disruption) for affected systems. Impacting 2 products from linux, from debian organizations running these solutions should prioritize assessment and patching.
Reported in 2025, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.
2025-05-02T15:15:48.557
2025-11-06T20:48:20.637
Analyzed
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSSv3.1: 7.8 (HIGH)
| Type | Vendor | Product | Version/Range | Vulnerable? |
|---|---|---|---|---|
| Operating System | linux | linux_kernel | < 5.4.293 | Yes |
| Operating System | linux | linux_kernel | < 5.10.237 | Yes |
| Operating System | linux | linux_kernel | < 5.15.181 | Yes |
| Operating System | linux | linux_kernel | < 6.1.136 | Yes |
| Operating System | linux | linux_kernel | < 6.6.89 | Yes |
| Operating System | linux | linux_kernel | < 6.12.26 | Yes |
| Operating System | linux | linux_kernel | < 6.14.5 | Yes |
| Operating System | linux | linux_kernel | 4.14 | Yes |
| Operating System | linux | linux_kernel | 4.14 | Yes |
| Operating System | linux | linux_kernel | 4.14 | Yes |
| Operating System | linux | linux_kernel | 4.14 | Yes |
| Operating System | linux | linux_kernel | 4.14 | Yes |
| Operating System | linux | linux_kernel | 4.14 | Yes |
| Operating System | linux | linux_kernel | 4.14 | Yes |
| Operating System | linux | linux_kernel | 4.14 | Yes |
| Operating System | linux | linux_kernel | 6.15 | Yes |
| Operating System | linux | linux_kernel | 6.15 | Yes |
| Operating System | linux | linux_kernel | 6.15 | Yes |
| Operating System | debian | debian_linux | 11.0 | Yes |
SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For linux's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.