Executive brief
A vulnerability was identified in the Linux kernel's Netfilter subsystem, which handles network traffic filtering and connection tracking. A technical error in how the system manages memory references for connection 'expectations' could lead to resource management issues. While primarily a maintenance fix, unresolved memory references in the kernel can eventually impact system stability or performance.
Technical details
A reference leak exists in net/netfilter/nft_ct.c within the nft_ct_expect_obj_eval() function. The function allocates a connection tracking expectation and may call nf_ct_expect_related(), but it fails to drop the local reference before returning. This results in a reference count imbalance. An attacker with the ability to trigger this code path (typically requiring local privileges to manipulate nftables) could potentially cause a kernel resource leak. The issue has been resolved by adding a call to nf_ct_expect_put(exp) to balance the allocation.
Affected products
- Linux Linux Kernel 5.3 to 6.6.141
Timeline
- 2026-05-07: other: Patch authored by Li Xiasong
- 2026-06-24: disclosed: CVE published
- 2026-06-24: advisory: NVD advisory published
References
- https://git.kernel.org/stable/c/19f94b6fee75b3ef7fbc06f3745b9a771a8a19a4
- https://git.kernel.org/stable/c/1dced0725e2fae3ac3416274db20a7ff5a46931d
- https://git.kernel.org/stable/c/26ab32ec73941871c97562ee1f39587950dc3b68
- https://git.kernel.org/stable/c/2aef1b13d5c0285f340512c6c07eb858fd018fd8
- https://git.kernel.org/stable/c/7b96242ceedfe249f158419f3254bcee04173ffe
- https://git.kernel.org/stable/c/84c422cea5a45fe56be839f25880f21fd33940cd
- https://git.kernel.org/stable/c/cdb9a25dd3416d427e8b2753210f8baf44207577