CVE-2025-39766 is a vulnerability in the Linux kernel's networking scheduler, specifically within the cake_enqueue function, affecting Debian and other Linux distributions. It arises when a low memory limit in the "cake" qdisc causes packet dropping, but the function incorrectly returns NET_XMIT_SUCCESS instead of NET_XMIT_CN, leading to a WARNING in htb_activate. This vulnerability is rated High severity (CVSS 7.8), indicating a local attack vector with low complexity that could result in high impact to confidentiality, integrity, and availability. There is currently no known active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or KEV listing, though it has garnered some community discussion and media coverage.
| Vendor | Product | Version(s) | CPE |
|---|---|---|---|
>= 4.19, < 5.4.297CPE matchmatch criteria | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | ||
>= 5.5, < 5.10.241CPE matchmatch criteria | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | ||
>= 5.11, < 5.15.190CPE matchmatch criteria | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | ||
>= 5.16, < 6.1.149CPE matchmatch criteria | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | ||
>= 6.2, < 6.6.103CPE matchmatch criteria | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
CVSS version used by this source: 3.1
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.2 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.
The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.
Linux kernel (Azure) vulnerabilities
Mar 25, 2026Linux kernel (Azure FIPS) vulnerabilities
Mar 4, 2026Linux kernel (Azure) vulnerabilities
Mar 4, 2026Linux kernel (Xilinx) vulnerabilities
Feb 24, 2026Linux kernel (IBM) vulnerabilities
Feb 24, 2026kernel: net/sched: Make cake_enqueue return NET_XMIT_CN when past buffer_limit
Sep 11, 2025net/sched: Make cake_enqueue return NET_XMIT_CN when past buffer_limit
Sep 9, 2025