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CVE-2026-64269— RDMA/rtrs-srv: Bound RDMA-Write length to chunk size in rdma_write_sg

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会开源的一款操作系统内核。 Linux kernel 5.8版本存在安全漏洞，该漏洞源于RDMA rtrs-srv中rdma_write_sg函数未对desc[0].len参数进行正确的长度检查，导致远程攻击者可以控制该参数使RDMA写长度超过max_chunk_size，从而可能造成主机内存信息泄露或连接异常终止。

CVSS 9.1 · Critical EPSS 0.71% · P53

Possible ATT&CK Techniques 1 AI

T1115 · Clipboard Data

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux 9cb837480424e78ed585376f944088246685aec3< a35b7a8728a53ddc80b323970689fa5985816836 affected
9cb837480424e78ed585376f944088246685aec3< 68c09762172f6224e9ddf9b0a60bacbb36e443eb affected
9cb837480424e78ed585376f944088246685aec3< 6cada540150894e81042a0ae0c796a21a9a877da affected
9cb837480424e78ed585376f944088246685aec3< 2912f3d40355dabc08fdbaaf2764d02445fe88dc affected
9cb837480424e78ed585376f944088246685aec3< 6f40246f4312fdbab5a13cc440adebf95eb2aa66 affected
9cb837480424e78ed585376f944088246685aec3< 5a45d0aa1fa50a333ce5763ade744e2d89838667 affected
9cb837480424e78ed585376f944088246685aec3< da3e44add94b05dfde56f898421922f5cf35705f affected
9cb837480424e78ed585376f944088246685aec3< 963af8d97a8c6a117134a8d0db1415e0489200b1 affected
… +10 more rows
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I. Basic Information for CVE-2026-64269

Vulnerability Information
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Vulnerability Title
RDMA/rtrs-srv: Bound RDMA-Write length to chunk size in rdma_write_sg
Source: CVE Program / CVE List V5
Vulnerability 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).
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会开源的一款操作系统内核。 Linux kernel 5.8版本存在安全漏洞，该漏洞源于RDMA rtrs-srv中rdma_write_sg函数未对desc[0].len参数进行正确的长度检查，导致远程攻击者可以控制该参数使RDMA写长度超过max_chunk_size，从而可能造成主机内存信息泄露或连接异常终止。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 9cb837480424e78ed585376f944088246685aec3 ~ a35b7a8728a53ddc80b323970689fa5985816836 -
Linux Linux 5.8 -

II. Public POCs for CVE-2026-64269

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III. Intelligence Information for CVE-2026-64269

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Patches & Fixes for CVE-2026-64269 (7)

Same Patch Batch · Linux · 2026-07-25 · 274 CVEs total

CVE-2026-64355 9.8 CRITICAL bpf: Reject fragmented frames in devmap
CVE-2026-64459 9.8 CRITICAL tcp: restore RCU grace period in tcp_ao_destroy_sock
CVE-2026-64303 9.8 CRITICAL spi: fsl-lpspi: terminate the RX channel on TX prepare failure path
CVE-2026-64439 9.8 CRITICAL crypto: krb5 - filter out async aead implementations at alloc
CVE-2026-64410 9.8 CRITICAL netfilter: flowtable: IPIP tunnel hardware offload is not yet support
CVE-2026-64399 9.8 CRITICAL ksmbd: add permission checks for FSCTL_DUPLICATE_EXTENTS_TO_FILE
CVE-2026-64397 9.8 CRITICAL ksmbd: serialize QUERY_DIRECTORY requests per file
CVE-2026-64391 9.8 CRITICAL ksmbd: use opener credentials for ADS I/O
CVE-2026-64387 9.8 CRITICAL smb: client: fix query directory replay double-free
CVE-2026-64386 9.8 CRITICAL smb: client: fix query_info() replay double-free
CVE-2026-64385 9.8 CRITICAL smb: client: fix double-free in SMB2_ioctl() replay
CVE-2026-64383 9.8 CRITICAL smb: client: fix double-free in SMB2_flush() replay
CVE-2026-64384 9.8 CRITICAL smb: client: fix change notify replay double-free
CVE-2026-64268 9.8 CRITICAL RDMA/siw: bound Read Response placement to the RREAD length
CVE-2026-64523 9.8 CRITICAL net/handshake: Take a long-lived file reference at submit
CVE-2026-64450 9.1 CRITICAL tipc: fix out-of-bounds read in broadcast Gap ACK blocks
CVE-2026-64392 9.1 CRITICAL ksmbd: use opener credentials for delete-on-close
CVE-2026-64393 9.1 CRITICAL ksmbd: run set info with opener credentials
CVE-2026-64257 9.1 CRITICAL smb: client: reject overlapping data areas in SMB2 responses
CVE-2026-64319 9.1 CRITICAL nvmet-auth: validate reply message payload bounds against transfer length

Showing top 20 of 274 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

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Same vendor: Linux

V. Comments for CVE-2026-64269

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