CVE-2026-64102

CVE CVE-2026-64102EUVD EUVD-2026-45787Veröffentlicht 2026-07-19T15:40:06.000ZZuletzt geändert 2026-08-05T12:39:14.000ZCVSS 9.8

Was das Advisory beschreibt

In the Linux kernel, the following vulnerability has been resolved: RDMA/siw: Reject MPA FPDU length underflow before signed receive math A malicious connected siw peer can send an iWARP FPDU whose MPA length field (c_hdr->mpa_len, 16 bit big-endian, peer-controlled) is smaller than the fixed DDP/RDMAP header for the announced opcode. Soft-iWARP parses the full header in siw_get_hdr() based on iwarp_pktinfo[opcode] .hdr_len, but never compares mpa_len against that header length. siw_tcp_rx_data() then derives srx->fpdu_part_rem = be16_to_cpu(mpa_len) - fpdu_part_rcvd + MPA_HDR_SIZE; where fpdu_part_rcvd equals iwarp_pktinfo[opcode].hdr_len at this point. For a tagged WRITE (hdr_len 16, MPA_HDR_SIZE 2) the smallest on-wire mpa_len of 0 yields fpdu_part_rem = -14, and any mpa_len below hdr_len - MPA_HDR_SIZE underflows to a negative int. The signed value then flows into siw_proc_write()/siw_proc_rresp() as bytes = min(srx->fpdu_part_rem, srx->skb_new); is handed to siw_check_mem() as an int len (whose interval check addr + len > mem->va + mem->len is satisfied for a valid base when len is negative), and reaches siw_rx_data() -> siw_rx_kva() / siw_rx_umem() -> skb_copy_bits() as a signed copy length. The header copy branch in skb_copy_bits() promotes that to size_t, producing a multi-gigabyte read. KASAN under a KUnit harness that drives the real kernel TCP receive path -- a loopback AF_INET socketpair, the malformed FPDU written via kernel_sendmsg, sk_data_ready firing in softirq, tcp_read_sock dispatching to siw_tcp_rx_data -- reports: BUG: KASAN: use-after-free in skb_copy_bits+0x284/0x480 Read of size 4294967295 at addr ffff888... Call Trace: skb_copy_bits siw_rx_kva siw_rx_data siw_check_mem siw_proc_write siw_tcp_rx_data __tcp_read_sock siw_qp_llp_data_ready tcp_data_ready tcp_data_queue Add the missing invariant at the earliest point where the peer header is fully assembled. iwarp_pktinfo[*].hdr_len - MPA_HDR_SIZE is exactly the value the siw transmitter uses as the minimum mpa_len for each opcode (drivers/infiniband/sw/siw/siw_qp.c:33), so this matches the protocol contract. Out-of-range FPDUs terminate the connection with TERM_ERROR_LAYER_LLP / LLP_ETYPE_MPA / LLP_ECODE_FPDU_START -- which is RFC 5044 Section 8 error code 3 ("Marker and ULPDU Length fields do not agree on the start of an FPDU"), the correct framing-error class for this inconsistency.

Quelle: EUVD (ENISA), im Wortlaut der Meldung.

Produkte, die das Advisory nennt

Diese Angaben stammen aus der Meldung selbst, nicht aus einer Prüfung durch uns.

• Linux — Linux patch: 6.12.92; 8b6a361b8c482f22ac99c3273285ff16b23fba91 <1012896f4225e8f801ff3c1648023845b66dfb11; 5.3; 8b6a361b8c482f22ac99c3273285ff16b23fba91 <14553be882d9ce91749c9d64041de66e34ad8e70; patch: 7.1; 8b6a361b8c482f22ac99c3273285ff16b23fba91 <683f7cfbf514193d63c0efa079f3352bde84c2e0; patch: 7.0.11; patch: 5.10.258; 8b6a361b8c482f22ac99c3273285ff16b23fba91 <c7c0c0f4379dedec12d24dbb9dded5d2db7fd9f2; patch: 6.18.34; 8b6a361b8c482f22ac99c3273285ff16b23fba91 <33a8b5e971e294ec2a7b74211c545e09efd8e9ac; 8b6a361b8c482f22ac99c3273285ff16b23fba91 <0ce1bc9e46ecabe84772bb561e373c0d9876d6f2; 8b6a361b8c482f22ac99c3273285ff16b23fba91 <4a331582011d9e8089af8aa2a61ec6b4443bb245; patch: 6.6.142; patch: 6.1.175; patch: 0; 8b6a361b8c482f22ac99c3273285ff16b23fba91 <775b4dc9618a99a1fa48b57554041a5dc17e1336; patch: 5.15.209

Die genannten Versionen sind die Angabe der Meldung. Patchlage vergleicht keine Versionsnummern und leitet aus ihnen keine Aussage ab — welche Version installiert ist, muss ein Mensch nachsehen.

Im Produktkatalog geführt

Für diese Produkte kann ein Bestand in Patchlage erfasst werden. Ein Advisory dazu erscheint am Morgen danach im Lagebericht.

• Linux — Linux

Patchlage meldet Treffer und Verdachtsfälle. Zu allem anderen sagt dieses System nichts — weder diese Seite noch der Lagebericht behauptet je, dass ein Bestand sicher ist.