--- id: CVE-2026-64268 title: |- In the Linux kernel, the following vulnerability has been resolved: RDMA/siw: bound Read Response placement to the RREAD length In drivers/infiniband/sw/siw/siw_qp_rx.c, siw_proc_rresp() places each inbound Read Response DDP segment at… summary: |- In the Linux kernel, the following vulnerability has been resolved: RDMA/siw: bound Read Response placement to the RREAD length In drivers/infiniband/sw/siw/siw_qp_rx.c, siw_proc_rresp() places each inbound Read Response DDP segment at… severity: critical cvss: 9.8 cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H' published: '2026-07-25' updated: '2026-07-27' source: NVD sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-64268' references: - url: 'https://git.kernel.org/stable/c/3ef7e052cbd05a8b13a51a07b185a39ec93ee1cf' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/423a78ff7928c2601013f73ec6d896f5597d0df5' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/595e6537ad1a210da32cbb9a7f91aa73090915ba' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/6bc89f34a4597f9f6d41f7a60c67a3153bfe8851' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/75c93cd3c421890f49ea93f0b978b9b7bb10e5e3' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/7d29f7e9dbd844cae4d3e559cf78324b9642fd6b' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/a31b6d18ded3cc32d9ee85a6ff0726d4274887b2' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/b2e26c955f8dd7e8d3f16c858db05245ea4fa817' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: >- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64268.json - url: 'https://access.redhat.com/security/cve/CVE-2026-64268' - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2507089' - url: 'https://www.cve.org/CVERecord?id=CVE-2026-64268' - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-64268' - url: >- https://lore.kernel.org/linux-cve-announce/2026072559-CVE-2026-64268-629a@gregkh/T - url: 'https://access.redhat.com/errata/RHSA-2026:63129' - url: 'https://access.redhat.com/errata/RHSA-2026:63014' - url: 'https://access.redhat.com/errata/RHSA-2026:65710' - url: 'https://access.redhat.com/errata/RHSA-2026:63013' - url: 'https://access.redhat.com/errata/RHSA-2026:68100' - url: 'https://access.redhat.com/errata/RHSA-2026:67720' - url: 'https://access.redhat.com/errata/RHSA-2026:69837' tags: - nvd - csaf - vex - red-hat epss: 0.00714 epssPercentile: 0.51601 ingestedAt: '2026-07-27T06:16:49.723Z' vendor: Red Hat product: Red Hat Enterprise Linux BaseOS (v. 9) affected: - enterprise_linux 9 - enterprise_linux_appstream_v_9 - enterprise_linux_baseos_v_8 - enterprise_linux_baseos_aus_v_8_4 - enterprise_linux_baseos_eus_extension_v_8_4 - enterprise_linux_baseos_v_9 - enterprise_linux_crb_v_8 - enterprise_linux_codeready_linux_builder_v_9 - enterprise_linux_nfv_v_8 - enterprise_linux_real_time_for_nfv_v_9 - enterprise_linux_rt_v_8 - enterprise_linux_real_time_v_9 patched: - enterprise_linux_appstream_v_9 - enterprise_linux_baseos_v_8 - enterprise_linux_baseos_aus_v_8_4 - enterprise_linux_baseos_eus_extension_v_8_4 - enterprise_linux_baseos_v_9 - enterprise_linux_crb_v_8 - enterprise_linux_codeready_linux_builder_v_9 - enterprise_linux_nfv_v_8 - enterprise_linux_real_time_for_nfv_v_9 - enterprise_linux_rt_v_8 - enterprise_linux_real_time_v_9 cwe: - CWE-787 scores: nvd: 9.8 vendor: 8.8 --- ## Overview In the Linux kernel, the following vulnerability has been resolved: RDMA/siw: bound Read Response placement to the RREAD length In drivers/infiniband/sw/siw/siw_qp_rx.c, siw_proc_rresp() places each inbound Read Response DDP segment at sge->laddr + wqe->processed and then accumulates wqe->processed, but it never checks the running total against the sink buffer length on continuation segments. siw_check_sge() resolves and validates the sink memory only on the first fragment (the if (!*mem) branch), and siw_rresp_check_ntoh() compares the cumulative length against wqe->bytes only on the final segment (the !frx->more_ddp_segs guard). A connected siw peer that answers an outstanding RREAD with Read Response segments that keep the DDP Last flag clear, carrying more total payload than the RREAD requested, drives wqe->processed past the validated sink buffer; the next siw_rx_data() call writes out of bounds at sge->laddr + wqe->processed. siw runs iWARP over ordinary routable TCP, so the peer is the remote end of an established RDMA connection and needs no local privilege. Bound every segment before placement, exactly as siw_proc_send() and siw_proc_write() already do for their tagged and untagged paths, and terminate the connection with a base-or-bounds DDP error when the Read Response would overrun the sink buffer. This is the second receive-path length fix for this file. A separate change rejects an MPA FPDU length that underflows the per-fragment remainder in the header decode; that guard does not cover this case, because here each individual segment length is self-consistent and only the accumulated placement offset overruns the buffer. ## Remediation Refer to the linked advisories for vendor-supplied fixes and affected version ranges. ## Vendor advisories - **RHSA-2026:63129** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9), Red Hat Enterprise Linux Real Time for NFV (v. 9), Red Hat Enterprise Linux Real Time (v. 9) · released 2026-09-04 · [advisory](https://access.redhat.com/errata/RHSA-2026:63129) - **RHSA-2026:63014** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 8), Red Hat Enterprise Linux CRB (v. 8) · released 2026-09-03 · [advisory](https://access.redhat.com/errata/RHSA-2026:63014) - **RHSA-2026:65710** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS AUS (v.8.4), Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4) · released 2026-09-09 · [advisory](https://access.redhat.com/errata/RHSA-2026:65710) - **RHSA-2026:63013** · Red Hat · fixed in: Red Hat Enterprise Linux NFV (v. 8), Red Hat Enterprise Linux RT (v. 8) · released 2026-09-03 · [advisory](https://access.redhat.com/errata/RHSA-2026:63013) - **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 9 · updated 2026-09-22 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64268.json) - **RHSA-2026:68100** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream E4S (v.9.4), Red Hat Enterprise Linux BaseOS E4S (v.9.4), Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4), Red Hat Enterprise Linux Real Time E4S (v.9.4) · released 2026-09-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:68100) - **RHSA-2026:67720** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v.9.6), Red Hat Enterprise Linux BaseOS EUS (v.9.6), Red Hat CodeReady Linux Builder EUS (v.9.6), Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6), Red Hat Enterprise Linux Real Time EUS (v.9.6) · released 2026-09-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:67720) - **RHSA-2026:69837** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS E4S (v.8.8), Red Hat Enterprise Linux BaseOS TUS (v.8.8) · released 2026-09-22 · [advisory](https://access.redhat.com/errata/RHSA-2026:69837)