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CVE-2026-64456: Linux, грешка в паметта

7.7

CVSS 3.1

Няма данни

Вероятност да бъде експлоатирана в следващите 30 дни (EPSS)

Няма потвърждение

Атакува се

Няма данни

Време до експлоатация

Атакува се локално, без особени условия, без вход и без действие от потребителя.

CVE радар: още уязвимости от този вид

  • Експлоатация: няма данни за експлоатация
  • Атаката не може да се автоматизира

Описание

Оригинално описание

In the Linux kernel, the following vulnerability has been resolved: hwrng: virtio: clamp device-reported used.len at copy_data() random_recv_done() stores the device-reported used.len directly into vi->data_avail. copy_data() then indexes vi->data[] using vi->data_idx (advanced by previous copy_data() calls) and issues a memcpy() without re-validating either value against the posted buffer size sizeof(vi->data) (SMP_CACHE_BYTES bytes, typically 32 or 64). A malicious or buggy virtio-rng backend can set used.len beyond sizeof(vi->data), steering the memcpy() past the end of the inline array into adjacent kmalloc-1k slab bytes. hwrng_fillfn() mixes those bytes into the guest RNG, and guest root can also observe them directly via /dev/hwrng. Concrete impact is inside the guest: - Memory-safety / hardening: any virtio-rng backend that over-reports used.len causes the driver to read past vi->data into unrelated slab contents. hwrng_fillfn() is a kernel thread that runs as soon as the device is probed; no guest userspace interaction is required to first-trigger the OOB. - Cross-boundary leak (confidential-compute threat model): a malicious hypervisor cooperating with a malicious or compromised guest root userspace can use /dev/hwrng as a leak channel for guest-kernel heap data. The host sets a large used.len, guest root reads /dev/hwrng, and the returned bytes contain guest kernel slab contents that were adjacent to vi->data. In practice, confidential-compute guests (SEV-SNP, TDX) usually disable virtio-rng entirely, so this path is narrow, but the fix is still worth carrying because the underlying memory-safety bug contaminates the guest RNG on any host. KASAN confirms the OOB on a 7.1-rc4 guest whose virtio-rng backend has been patched to report used.len = 0x10000: BUG: KASAN: slab-out-of-bounds in virtio_read+0x394/0x5d0 Read of size 64 at addr ffff88800ae0ba20 by task hwrng/52 Call Trace: __asan_memcpy+0x2

Засегнати продукти

  • Linux Linux: f7f510ec195781c857ab76366a3e1c59e1caae42 преди 3aa3e89cf80721c8d382b4c1a2b70a0449dad4a5; f7f510ec195781c857ab76366a3e1c59e1caae42 преди 63335e7b638ae70028ae285bb95153874a8bc852; f7f510ec195781c857ab76366a3e1c59e1caae42 преди 2e788948ff2a13358a303af112497a63201c5739; f7f510ec195781c857ab76366a3e1c59e1caae42 преди fde19b0d4eeabae042519313c843fe6f27d41e9d; f7f510ec195781c857ab76366a3e1c59e1caae42 преди 81dd21b5f0c299cc7b5bf84f04a61938559d20e6; f7f510ec195781c857ab76366a3e1c59e1caae42 преди 285e17c44e3873a73460f294acbd64018ff64385; f7f510ec195781c857ab76366a3e1c59e1caae42 преди 92d5736a62040ec1cfff23ea57e6599301690ad5; f7f510ec195781c857ab76366a3e1c59e1caae42 преди e3046eeada299f917a8ad883af4434bfb86556b1
  • Linux Linux: 2.6.26; преди 2.6.26; 5.10.261 до 5.10.*; 5.15.212 до 5.15.*; 6.1.178 до 6.1.*; 6.6.145 до 6.6.*; 6.12.96 до 6.12.*; 6.18.39 до 6.18.*; 7.1.4 до 7.1.*; от 7.2 нататък

Вид слабост

История

  • 25 юли 2026 Публикувано

Други уязвимости в Linux Linux

Първоизточници

CVE-2026-64456: Linux, грешка в паметта | freedomonline.bg