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CVE-2026-68124: Linux

9.6

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 от съседна мрежа, без особени условия, без вход и без действие от потребителя.

    Описание

    Оригинално описание

    In the Linux kernel, the following vulnerability has been resolved: mctp: serial: handle zero-length frames to prevent rx buffer overflow The MCTP serial receive state machine reads a frame length byte in mctp_serial_push_header() case 2 and validates it upper-bound-only: if (c > MCTP_SERIAL_FRAME_MTU) { dev->rxstate = STATE_ERR; } else { dev->rxlen = c; dev->rxpos = 0; dev->rxstate = STATE_DATA; ... } A length of zero passes this check, so rxlen is set to 0 and the state machine advances to STATE_DATA. In mctp_serial_push() STATE_DATA, the incoming byte is stored and rxpos incremented before the terminator is dev->rxbuf[dev->rxpos] = c; dev->rxpos++; dev->rxstate = STATE_DATA; if (dev->rxpos == dev->rxlen) { dev->rxpos = 0; dev->rxstate = STATE_TRAILER; } With rxlen == 0 the "rxpos == rxlen" terminator can never fire (rxpos is already 1 on the first data byte), so subsequent bytes are written past the end of the fixed 74-byte rxbuf, which is the last member of the netdev private area. Every following data byte is an attacker-controlled 1-byte out-of-bounds heap write, and the overflow continues until a frame (0x7e) or escape byte resets the parser -- effectively unbounded. Reaching this requires CAP_NET_ADMIN to attach the N_MCTP line discipline and bring the resulting mctpserialN netdev up, after which the bytes arrive via the tty receive path. Route a zero-length frame straight to STATE_TRAILER instead of STATE_DATA. The trailer/framing bytes are still consumed, and the frame resolves to a zero-length skb that the MCTP core rejects; the parser never enters STATE_DATA with rxlen == 0, so the out-of-bounds write can no longer occur. KASAN, on a frame of 0x7e 0x01 0x00 followed by data bytes (before this change): UBSAN: array-index-out-of-bounds in drivers/net/mctp/mctp-serial.c:370 index 74 is out of range for type 'u8 [74]' BUG: KASAN: slab-out-of-bounds in mctp_serial_tty_receive_buf Write of size 1 at addr ... by task kwor

    Засегнати продукти

    • Linux Linux: a0c2ccd9b5ad0a9e838158404e041b5a8ff762dd преди 64b96ae7912244d55257aa330d9569ee0a8f8d99; a0c2ccd9b5ad0a9e838158404e041b5a8ff762dd преди 36dc6d6964a3b90411cc7944cd9b8b6f67b9807b; a0c2ccd9b5ad0a9e838158404e041b5a8ff762dd преди 68819427bc07eca7963a9e8be19e5272cc29186c; a0c2ccd9b5ad0a9e838158404e041b5a8ff762dd преди f80ba170d7b3a44e3d244a2c8e06031d61bf3b23; a0c2ccd9b5ad0a9e838158404e041b5a8ff762dd преди 06a6b606129c8a25cd457760f5370f3ff01fe05d; a0c2ccd9b5ad0a9e838158404e041b5a8ff762dd преди 793b9b729f1e8de57be8c8daf1a9838be96cabed
    • Linux Linux: 5.17; преди 5.17; 6.1.183 до 6.1.*; 6.6.148 до 6.6.*; 6.12.101 до 6.12.*; 6.18.42 до 6.18.*; 7.1.6 до 7.1.*; от 7.2 нататък

    История

    • 10 август 2026 Публикувано

    Други уязвимости в Linux Linux

    Първоизточници

    CVE-2026-68124: Linux | freedomonline.bg