FKIE_CVE-2026-64269

Vulnerability from fkie_nvd - Published: 2026-07-25 10:17 - Updated: 2026-07-27 05:16
Severity
9.1 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: RDMA/rtrs-srv: Bound RDMA-Write length to chunk size in rdma_write_sg When the server answers an RTRS READ, rdma_write_sg() builds the source scatter/gather entry for the IB_WR_RDMA_WRITE that returns data to the peer. Its length is taken directly from the wire descriptor: plist->length = le32_to_cpu(id->rd_msg->desc[0].len); rd_msg points into the chunk buffer that the remote peer filled via RDMA-WRITE-WITH-IMM (rtrs_srv_rdma_done() -> process_io_req() -> process_read()), so desc[0].len is attacker-controlled and, before this change, was only rejected when zero. The source address is the fixed chunk start (dma_addr[msg_id]) and the source lkey is the PD-wide local_dma_lkey, which is not tied to the chunk's MR mapping, so the verbs layer does not constrain the transfer length to max_chunk_size. msg_id and off are bounded against queue_depth and max_chunk_size in rtrs_srv_rdma_done(), but desc[0].len is a separate field that was not checked against the chunk size. A peer that advertises desc[0].len larger than max_chunk_size can make the posted RDMA write read past the chunk's mapped region. The resulting behaviour depends on the IOMMU configuration: with no IOMMU or in passthrough mode the read may extend into memory adjacent to the chunk and be returned to the peer, which can disclose host memory; with a translating IOMMU the out-of-range access is expected to fault and abort the connection. In either case the transfer exceeds what the protocol permits and is driven by a remote peer. Reject a descriptor length above max_chunk_size, mirroring the existing off >= max_chunk_size bound in rtrs_srv_rdma_done(). Legitimate clients do not exceed it: the client sets desc[0].len to its MR length, which is capped at the negotiated max_io_size (max_chunk_size - MAX_HDR_SIZE).
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2912f3d40355dabc08fdbaaf2764d02445fe88dc
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5a45d0aa1fa50a333ce5763ade744e2d89838667
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/68c09762172f6224e9ddf9b0a60bacbb36e443eb
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6cada540150894e81042a0ae0c796a21a9a877da
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6f40246f4312fdbab5a13cc440adebf95eb2aa66
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/963af8d97a8c6a117134a8d0db1415e0489200b1
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/da3e44add94b05dfde56f898421922f5cf35705f
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/infiniband/ulp/rtrs/rtrs-srv.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "68c09762172f6224e9ddf9b0a60bacbb36e443eb",
              "status": "affected",
              "version": "9cb837480424e78ed585376f944088246685aec3",
              "versionType": "git"
            },
            {
              "lessThan": "6cada540150894e81042a0ae0c796a21a9a877da",
              "status": "affected",
              "version": "9cb837480424e78ed585376f944088246685aec3",
              "versionType": "git"
            },
            {
              "lessThan": "2912f3d40355dabc08fdbaaf2764d02445fe88dc",
              "status": "affected",
              "version": "9cb837480424e78ed585376f944088246685aec3",
              "versionType": "git"
            },
            {
              "lessThan": "6f40246f4312fdbab5a13cc440adebf95eb2aa66",
              "status": "affected",
              "version": "9cb837480424e78ed585376f944088246685aec3",
              "versionType": "git"
            },
            {
              "lessThan": "5a45d0aa1fa50a333ce5763ade744e2d89838667",
              "status": "affected",
              "version": "9cb837480424e78ed585376f944088246685aec3",
              "versionType": "git"
            },
            {
              "lessThan": "da3e44add94b05dfde56f898421922f5cf35705f",
              "status": "affected",
              "version": "9cb837480424e78ed585376f944088246685aec3",
              "versionType": "git"
            },
            {
              "lessThan": "963af8d97a8c6a117134a8d0db1415e0489200b1",
              "status": "affected",
              "version": "9cb837480424e78ed585376f944088246685aec3",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/infiniband/ulp/rtrs/rtrs-srv.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.8"
            },
            {
              "lessThan": "5.8",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.212",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.96",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.39",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/rtrs-srv: Bound RDMA-Write length to chunk size in rdma_write_sg\n\nWhen the server answers an RTRS READ, rdma_write_sg() builds the source\nscatter/gather entry for the IB_WR_RDMA_WRITE that returns data to the\npeer. Its length is taken directly from the wire descriptor:\n\n  plist-\u003elength = le32_to_cpu(id-\u003erd_msg-\u003edesc[0].len);\n\nrd_msg points into the chunk buffer that the remote peer filled via\nRDMA-WRITE-WITH-IMM (rtrs_srv_rdma_done() -\u003e process_io_req() -\u003e\nprocess_read()), so desc[0].len is attacker-controlled and, before this\nchange, was only rejected when zero. The source address is the fixed\nchunk start (dma_addr[msg_id]) and the source lkey is the PD-wide\nlocal_dma_lkey, which is not tied to the chunk\u0027s MR mapping, so the verbs\nlayer does not constrain the transfer length to max_chunk_size. msg_id\nand off are bounded against queue_depth and max_chunk_size in\nrtrs_srv_rdma_done(), but desc[0].len is a separate field that was not\nchecked against the chunk size.\n\nA peer that advertises desc[0].len larger than max_chunk_size can make\nthe posted RDMA write read past the chunk\u0027s mapped region. The resulting\nbehaviour depends on the IOMMU configuration: with no IOMMU or in\npassthrough mode the read may extend into memory adjacent to the chunk\nand be returned to the peer, which can disclose host memory; with a\ntranslating IOMMU the out-of-range access is expected to fault and abort\nthe connection. In either case the transfer exceeds what the protocol\npermits and is driven by a remote peer.\n\nReject a descriptor length above max_chunk_size, mirroring the existing\noff \u003e= max_chunk_size bound in rtrs_srv_rdma_done(). Legitimate clients\ndo not exceed it: the client sets desc[0].len to its MR length, which is\ncapped at the negotiated max_io_size (max_chunk_size - MAX_HDR_SIZE)."
    }
  ],
  "id": "CVE-2026-64269",
  "lastModified": "2026-07-27T05:16:38.830",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.1,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.2,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-07-25T10:17:07.160",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2912f3d40355dabc08fdbaaf2764d02445fe88dc"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5a45d0aa1fa50a333ce5763ade744e2d89838667"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/68c09762172f6224e9ddf9b0a60bacbb36e443eb"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6cada540150894e81042a0ae0c796a21a9a877da"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6f40246f4312fdbab5a13cc440adebf95eb2aa66"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/963af8d97a8c6a117134a8d0db1415e0489200b1"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/da3e44add94b05dfde56f898421922f5cf35705f"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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