What’s Vulnerable › Vulnerabilities

CVE-2025-40279: net: sched: act_connmark: initialize struct tc_ife to fix kernel leak

• Severity: unknown
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-12-06 · updated 2026-10-15

Description

In the Linux kernel, the following vulnerability has been resolved: net: sched: act_connmark: initialize struct tc_ife to fix kernel leak In tcf_connmark_dump(), the variable 'opt' was partially initialized using a designatied initializer. While the padding bytes are reamined uninitialized. nla_put() copies the entire structure into a netlink message, these uninitialized bytes leaked to userspace. Initialize the structure with memset before assigning its fields to ensure all members and padding are cleared prior to beign copied.

Affected products

• Linux kernel: 4.0 — fixed in 6.18

How to fix

Upgrade to a fixed version: Linux kernel 6.18. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/218b67c8c8246d47a2a7910eae80abe4861fe2b7
• https://git.kernel.org/stable/c/25837889ec062f2b7618142cd80253dff3da5343
• https://git.kernel.org/stable/c/31e4aa93e2e5b5647fc235b0f6ee329646878f9e
• https://git.kernel.org/stable/c/51cb05d4fd632596816ba44e882e84db9fb28a7e
• https://git.kernel.org/stable/c/62b656e43eaeae445a39cd8021a4f47065af4389
• https://git.kernel.org/stable/c/73cc56c608c209d3d666cc571293b090a471da70

Get alerted when CVE-2025-40279 or the next vulnerability affects your stack