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CVE PROGRAM SOURCE RECORD9.8 Critical

CVE-2026-89530

svcrdma: Reject inline replies that overflow the pull-up buffer

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: svcrdma: Reject inline replies that overflow the pull-up buffer An RPC-over-RDMA client can request a reply, such as an NFS READ payload, without providing a Write list or a Reply chunk to carry it. When such a reply needs more scatter/gather entries than the device's Send Queue supports, svc_rdma_pull_up_needed() selects pull-up and svc_rdma_pull_up_reply_msg() linearizes the whole reply into sctxt->sc_xprt_buf. That buffer is only sc_max_req_size bytes, while the reply on this path is bounded only by the client's request, so svc_rdma_xb_linearize() copies past the end of the buffer and corrupts adjacent slab memory. The oversized length is then stored in sc_sges[0].length and posted, so the device also reads beyond the mapped region. The SGE-exhaustion branch is the only pull-up path that can exceed the buffer: the threshold branch pulls up only replies smaller than RPCRDMA_PULLUP_THRESH, and replies that fit the device's SGE budget are sent directly without linearization. Make svc_rdma_pull_up_needed() report -E2BIG when the reply it would pull up cannot fit sc_max_req_size, and fail the request with ERR_CHUNK as RFC 8166 Section 4.5.3 directs rather than dropping the connection. The helper no longer answers a simple yes/no question: it now reports pull-up, no pull-up, or -E2BIG for a reply too large to linearize. Rename svc_rdma_pull_up_needed() to svc_rdma_check_pull_up() so its name no longer implies a boolean predicate.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • e248aa7be86e8179f20ac0931774ecd746f3f5bf to < b73011049dbe909f73fd9620d94ef1757d7af2ebaffected
  • e248aa7be86e8179f20ac0931774ecd746f3f5bf to < 8068358f445a11296328ffa7c524701596814a17affected
  • e248aa7be86e8179f20ac0931774ecd746f3f5bf to < fcd91b9957462d398792201c239dffaeff1cc8b2affected
  • e248aa7be86e8179f20ac0931774ecd746f3f5bf to < 1949dd1576f7a8aa161b1330c6125df9d53046d5affected
  • e248aa7be86e8179f20ac0931774ecd746f3f5bf to < 8ec60eb51fae37cd3d334ff26e4a7d6fb21ff7cfaffected
  • e248aa7be86e8179f20ac0931774ecd746f3f5bf to < 0fbe20dfe74b783d255bf389a6ea77aa25dc7860affected
  • 9b65b18f817d9ada2bf67351f24bdcce6789a0bbaffected
  • d564356e1919d1178568c19af410cfc1a9076663affected
  • 4.19.22 to < 4.20affected
  • 4.20.9 to < 4.21affected

Linux Linux

Default version status: affected

  • 5.0affected
  • 0 to < 5.0unaffected
  • 6.1.191 to ≤ 6.1.*unaffected
  • 6.6.160 to ≤ 6.6.*unaffected
  • 6.12.109 to ≤ 6.12.*unaffected
  • 6.18.50 to ≤ 6.18.*unaffected
  • 7.2.4 to ≤ 7.2.*unaffected
  • 7.3 to ≤ *unaffected

References