CVE-2026-53079

In the Linux kernel, the following vulnerability has been resolved:

net_sched: fix skb memory leak in deferred qdisc drops

When the network stack cleans up the deferred list via qdisc_run_end(), it operates on the root qdisc. If the root qdisc do not implement the TCQ_F_DEQUEUE_DROPS flag the packets queue to free are never freed and gets stranded on the childs local to_free list.

Fix this by making qdisc_dequeue_drop() aware of the root qdisc. It fetches the root qdisc and check for the TCQ_F_DEQUEUE_DROPS flag. If the flag is present, the packet is appended directly to the roots to_free list. Otherwise, drop it directly as it was done before the optimization was implemented.

Weakness

The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.

Affected Software

Potential Mitigations

• Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone.
• For example, glibc in Linux provides protection against free of invalid pointers.
• When using Xcode to target OS X or iOS, enable automatic reference counting (ARC) [REF-391].
• To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std::auto_ptr (defined by ISO/IEC ISO/IEC 14882:2003), std::shared_ptr and std::unique_ptr (specified by an upcoming revision of the C++ standard, informally referred to as C++ 1x), or equivalent solutions such as Boost.

References

• https://git.kernel.org/stable/c/a6bd339dbb3514bce690fdcf252e788dfab4ee76
• https://git.kernel.org/stable/c/bf26ad92ffda7884825d67b46bd5efe615c3babf