CVE-2025-38177: sch_hfsc: make hfsc_qlen_notify() idempotent
In the Linux kernel, the following vulnerability has been resolved:
schhfsc: make hfscqlennotify() idempotent
hfscqlennotify() is not idempotent either and not friendly to its callers, like fqcodeldequeue(). Let's make it idempotent to ease qdisctreereducebacklog() callers' life:
1. updatevf() decreases cl->clnactive, so we can check whether it is non-zero before calling it.
2. eltreeremove() always removes RB node cl->elnode, but we can use RBEMPTYNODE() + RBCLEARNODE() to make it safe.
Affected Software
Remediation
Event History
Peer vulnerabilities
Found alongside the following vulnerabilities.
- CVE-2026-5291
- CVE-2026-4679
- CVE-2026-4449
- CVE-2026-4674
- CVE-2026-4442
- CVE-2026-4451
- CVE-2026-5292
- CVE-2026-5282
- CVE-2026-3922
- CVE-2026-5280
- CVE-2026-4458
- CVE-2026-3923
- CVE-2026-4462
- CVE-2026-4454
- CVE-2026-4675
- CVE-2025-37752
- CVE-2025-37756
- CVE-2025-37797
- CVE-2025-37890
- CVE-2025-37997
- CVE-2025-38000
- CVE-2025-38001
- CVE-2025-38083
- CVE-2025-38350
- CVE-2025-38477
- CVE-2025-38616
- CVE-2025-38617
- CVE-2025-38618
Frequently Asked Questions
What is the severity of CVE-2025-38177?
CVE-2025-38177 has a moderate severity rating due to its impact on the Linux kernel's queuing discipline.
What does CVE-2025-38177 affect?
CVE-2025-38177 affects the Linux Kernel's hfsc_qlen_notify() function and its interaction with other queuing mechanisms.
How do I fix CVE-2025-38177?
To fix CVE-2025-38177, update your Linux Kernel to the latest version where the vulnerability has been resolved.
What is hfsc_qlen_notify() in relation to CVE-2025-38177?
hfsc_qlen_notify() is a function in the Linux kernel that needed to be made idempotent to improve its compatibility with other queue management functions.
Why is CVE-2025-38177 a concern for Linux users?
CVE-2025-38177 is a concern for Linux users as it can potentially lead to inefficiencies in packet queuing and network performance.