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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-64269
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-25 10:17:07 UTC
Updated2026-07-30 15:00:27 UTC
DescriptionIn 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).

Risk And Classification

Primary CVSS: v3.1 9.1 CRITICAL from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

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

EPSS: 0.006790000 probability, percentile 0.487970000 (date 2026-08-01)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary9.1CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
3.1CNADECLARED9.1CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
High

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 9cb837480424e78ed585376f944088246685aec3 68c09762172f6224e9ddf9b0a60bacbb36e443eb git Not specified
CNA Linux Linux affected 9cb837480424e78ed585376f944088246685aec3 6cada540150894e81042a0ae0c796a21a9a877da git Not specified
CNA Linux Linux affected 9cb837480424e78ed585376f944088246685aec3 2912f3d40355dabc08fdbaaf2764d02445fe88dc git Not specified
CNA Linux Linux affected 9cb837480424e78ed585376f944088246685aec3 6f40246f4312fdbab5a13cc440adebf95eb2aa66 git Not specified
CNA Linux Linux affected 9cb837480424e78ed585376f944088246685aec3 5a45d0aa1fa50a333ce5763ade744e2d89838667 git Not specified
CNA Linux Linux affected 9cb837480424e78ed585376f944088246685aec3 da3e44add94b05dfde56f898421922f5cf35705f git Not specified
CNA Linux Linux affected 9cb837480424e78ed585376f944088246685aec3 963af8d97a8c6a117134a8d0db1415e0489200b1 git Not specified
CNA Linux Linux affected 5.8 Not specified
CNA Linux Linux unaffected 5.8 semver Not specified
CNA Linux Linux unaffected 5.15.212 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.178 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.145 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.96 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.39 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.4 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/6cada540150894e81042a0ae0c796a21a9a877da 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/2912f3d40355dabc08fdbaaf2764d02445fe88dc 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/5a45d0aa1fa50a333ce5763ade744e2d89838667 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/68c09762172f6224e9ddf9b0a60bacbb36e443eb 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/6f40246f4312fdbab5a13cc440adebf95eb2aa66 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/da3e44add94b05dfde56f898421922f5cf35705f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/963af8d97a8c6a117134a8d0db1415e0489200b1 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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