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CVE-2026-23086: Linux, отказ на услуга

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Описание

Оригинално описание

In the Linux kernel, the following vulnerability has been resolved: vsock/virtio: cap TX credit to local buffer size The virtio transports derives its TX credit directly from peer_buf_alloc, which is set from the remote endpoint's SO_VM_SOCKETS_BUFFER_SIZE value. On the host side this means that the amount of data we are willing to queue for a connection is scaled by a guest-chosen buffer size, rather than the host's own vsock configuration. A malicious guest can advertise a large buffer and read slowly, causing the host to allocate a correspondingly large amount of sk_buff memory. The same thing would happen in the guest with a malicious host, since virtio transports share the same code base. Introduce a small helper, virtio_transport_tx_buf_size(), that returns min(peer_buf_alloc, buf_alloc), and use it wherever we consume peer_buf_alloc. This ensures the effective TX window is bounded by both the peer's advertised buffer and our own buf_alloc (already clamped to buffer_max_size via SO_VM_SOCKETS_BUFFER_MAX_SIZE), so a remote peer cannot force the other to queue more data than allowed by its own vsock settings. On an unpatched Ubuntu 22.04 host (~64 GiB RAM), running a PoC with 32 guest vsock connections advertising 2 GiB each and reading slowly drove Slab/SUnreclaim from ~0.5 GiB to ~57 GiB; the system only recovered after killing the QEMU process. That said, if QEMU memory is limited with cgroups, the maximum memory used will be limited. With this patch applied: Before: MemFree: ~61.6 GiB Slab: ~142 MiB SUnreclaim: ~117 MiB After 32 high-credit connections: MemFree: ~61.5 GiB Slab: ~178 MiB SUnreclaim: ~152 MiB Only ~35 MiB increase in Slab/SUnreclaim, no host OOM, and the guest remains responsive. Compatibility with non-virtio transports: - VMCI uses the AF_VSOCK buffer knobs to size its queue pairs per socket based on the local vsk->buffer_* values; the remote side cann

Засегнати продукти

  • Linux Linux: 06a8fc78367d070720af960dcecec917d3ae5f3b преди fef7110ae5617555c792a2bb4d27878d84583adf; 06a8fc78367d070720af960dcecec917d3ae5f3b преди d9d5f222558b42f6277eafaaa6080966faf37676; 06a8fc78367d070720af960dcecec917d3ae5f3b преди c0e42fb0e054c2b2ec4ee80f48ccd256ae0227ce; 06a8fc78367d070720af960dcecec917d3ae5f3b преди 84ef86aa7120449828d1e0ce438c499014839711; 06a8fc78367d070720af960dcecec917d3ae5f3b преди 8ee784fdf006cbe8739cfa093f54d326cbf54037
  • Linux Linux: 4.8; преди 4.8; 6.1.162 до 6.1.*; 6.6.122 до 6.6.*; 6.12.68 до 6.12.*; 6.18.8 до 6.18.*; от 6.19 нататък
  • Siemens: още 3 продукта, добавени от Siemens

    SIMATIC S7-1500 CPU 1518-4 PN/DP MFP, SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP, SIPLUS S7-1500 CPU 1518-4 PN/DP MFP

Вид слабост

История

  • 4 февруари 2026 Публикувано

Други уязвимости в Linux Linux

Първоизточници

CVE-2026-23086: Linux, отказ на услуга | freedomonline.bg