Vulnerability-Lookup

CVE-2026-64269 (GCVE-0-2026-64269)

Vulnerability from cvelistv5 – Published: 2026-07-25 08:49 – Updated: 2026-07-27 04:59

Title

RDMA/rtrs-srv: Bound RDMA-Write length to chunk size in rdma_write_sg

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).

Severity

9.1 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Assigner

Linux

References

7 references

URL	Tags
https://git.kernel.org/stable/c/68c09762172f6224e…
https://git.kernel.org/stable/c/6cada540150894e81…
https://git.kernel.org/stable/c/2912f3d40355dabc0…
https://git.kernel.org/stable/c/6f40246f4312fdbab…
https://git.kernel.org/stable/c/5a45d0aa1fa50a333…
https://git.kernel.org/stable/c/da3e44add94b05dfd…
https://git.kernel.org/stable/c/963af8d97a8c6a117…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 9cb837480424e78ed585376f944088246685aec3 , < 68c09762172f6224e9ddf9b0a60bacbb36e443eb (git) Affected: 9cb837480424e78ed585376f944088246685aec3 , < 6cada540150894e81042a0ae0c796a21a9a877da (git) Affected: 9cb837480424e78ed585376f944088246685aec3 , < 2912f3d40355dabc08fdbaaf2764d02445fe88dc (git) Affected: 9cb837480424e78ed585376f944088246685aec3 , < 6f40246f4312fdbab5a13cc440adebf95eb2aa66 (git) Affected: 9cb837480424e78ed585376f944088246685aec3 , < 5a45d0aa1fa50a333ce5763ade744e2d89838667 (git) Affected: 9cb837480424e78ed585376f944088246685aec3 , < da3e44add94b05dfde56f898421922f5cf35705f (git) Affected: 9cb837480424e78ed585376f944088246685aec3 , < 963af8d97a8c6a117134a8d0db1415e0489200b1 (git)
Linux	Linux	Affected: 5.8 Unaffected: 0 , < 5.8 (semver) Unaffected: 5.15.212 , ≤ 5.15.* (semver) Unaffected: 6.1.178 , ≤ 6.1.* (semver) Unaffected: 6.6.145 , ≤ 6.6.* (semver) Unaffected: 6.12.96 , ≤ 6.12.* (semver) Unaffected: 6.18.39 , ≤ 6.18.* (semver) Unaffected: 7.1.4 , ≤ 7.1.* (semver) Unaffected: 7.2-rc1 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

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    "redhat_vex": {
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      "cve": "CVE-2026-64269",
      "id": "CVE-2026-64269",
      "initial_release_date": "2026-07-25T00:00:00+00:00",
      "product_status:known_not_affected": "275",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: RDMA/rtrs-srv: Bound RDMA-Write length to chunk size in rdma_write_sg",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64269.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "not set",
      "current_release_date": "2026-07-25T16:46:56Z",
      "cve": "CVE-2026-64269",
      "id": "CVE-2026-64269",
      "initial_release_date": "2026-07-25T16:46:56Z",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-64269",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-64269.json",
      "version": "2"
    }
  }
}

GHSA-FFXC-RC5X-R6RP

Vulnerability from github – Published: 2026-07-25 12:31 – Updated: 2026-07-27 06:30

Details

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).

Severity

9.1 (Critical)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2026-64269"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-25T10:17:07Z",
    "severity": "CRITICAL"
  },
  "details": "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": "GHSA-ffxc-rc5x-r6rp",
  "modified": "2026-07-27T06:30:31Z",
  "published": "2026-07-25T12:31:28Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64269"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2912f3d40355dabc08fdbaaf2764d02445fe88dc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5a45d0aa1fa50a333ce5763ade744e2d89838667"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/68c09762172f6224e9ddf9b0a60bacbb36e443eb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6cada540150894e81042a0ae0c796a21a9a877da"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6f40246f4312fdbab5a13cc440adebf95eb2aa66"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/963af8d97a8c6a117134a8d0db1415e0489200b1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/da3e44add94b05dfde56f898421922f5cf35705f"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

Action not permitted

CVE-2026-64269 (GCVE-0-2026-64269)

GHSA-FFXC-RC5X-R6RP

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