CVE-2026-64269RDMA/rtrs-srv: Bound RDMA-Write length to chunk size in rdma_write_sg
- 9.1CriticalCVSS base score
- 0.71%Exploitation in 30 daysEPSS · top 46% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
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).
Timeline
ID reserved
By Linux
- 6 days later
· 6 days later
Published
- 29 days later
· 29 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | Critical9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H |
| NVDNVD · Modified | 3.1 | Critical9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.71% · top 46% of all CVEs (12 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.1.
Affected products
- affected 9cb837480424e78ed585376f944088246685aec3 – < a35b7a8728a53ddc80b323970689fa5985816836
- affected 9cb837480424e78ed585376f944088246685aec3 – < 68c09762172f6224e9ddf9b0a60bacbb36e443eb
- affected 9cb837480424e78ed585376f944088246685aec3 – < 6cada540150894e81042a0ae0c796a21a9a877da
- affected 9cb837480424e78ed585376f944088246685aec3 – < 2912f3d40355dabc08fdbaaf2764d02445fe88dc
- affected 9cb837480424e78ed585376f944088246685aec3 – < 6f40246f4312fdbab5a13cc440adebf95eb2aa66
- affected 9cb837480424e78ed585376f944088246685aec3 – < 5a45d0aa1fa50a333ce5763ade744e2d89838667
- affected 9cb837480424e78ed585376f944088246685aec3 – < da3e44add94b05dfde56f898421922f5cf35705f
- affected 9cb837480424e78ed585376f944088246685aec3 – < 963af8d97a8c6a117134a8d0db1415e0489200b1
- affected 5.8
- unaffected < 5.8
- unaffected 5.10.266 – ≤ 5.10.*
- unaffected 5.15.212 – ≤ 5.15.*
- unaffected 6.1.178 – ≤ 6.1.*
- unaffected 6.6.145 – ≤ 6.6.*
- unaffected 6.12.96 – ≤ 6.12.*
- unaffected 6.18.39 – ≤ 6.18.*
- unaffected 7.1.4 – ≤ 7.1.*
- unaffected 7.2 – ≤ *
References
References8
- https://git.kernel.org/stable/c/a35b7a8728a53ddc80b323970689fa5985816836 (opens in a new tab)
- https://git.kernel.org/stable/c/68c09762172f6224e9ddf9b0a60bacbb36e443eb (opens in a new tab)
- https://git.kernel.org/stable/c/6cada540150894e81042a0ae0c796a21a9a877da (opens in a new tab)
- https://git.kernel.org/stable/c/2912f3d40355dabc08fdbaaf2764d02445fe88dc (opens in a new tab)
- https://git.kernel.org/stable/c/6f40246f4312fdbab5a13cc440adebf95eb2aa66 (opens in a new tab)
- https://git.kernel.org/stable/c/5a45d0aa1fa50a333ce5763ade744e2d89838667 (opens in a new tab)
- https://git.kernel.org/stable/c/da3e44add94b05dfde56f898421922f5cf35705f (opens in a new tab)
- https://git.kernel.org/stable/c/963af8d97a8c6a117134a8d0db1415e0489200b1 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-48981 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-64269)Record last updated .