CVE-2026-64268 - Vulnerability Details

- RDMA/siw: bound Read Response placement to the RREAD length

Description

In the Linux kernel, the following vulnerability has been resolved:

RDMA/siw: bound Read Response placement to the RREAD length

In drivers/infiniband/sw/siw/siw_qp_rx.c, siw_proc_rresp() places each
inbound Read Response DDP segment at sge->laddr + wqe->processed and then
accumulates wqe->processed, but it never checks the running total against
the sink buffer length on continuation segments. siw_check_sge() resolves
and validates the sink memory only on the first fragment (the if (!*mem)
branch), and siw_rresp_check_ntoh() compares the cumulative length against
wqe->bytes only on the final segment (the !frx->more_ddp_segs guard).

A connected siw peer that answers an outstanding RREAD with Read Response
segments that keep the DDP Last flag clear, carrying more total payload
than the RREAD requested, drives wqe->processed past the validated sink
buffer; the next siw_rx_data() call writes out of bounds at
sge->laddr + wqe->processed. siw runs iWARP over ordinary routable TCP,
so the peer is the remote end of an established RDMA connection and needs
no local privilege.

Bound every segment before placement, exactly as siw_proc_send() and
siw_proc_write() already do for their tagged and untagged paths, and
terminate the connection with a base-or-bounds DDP error when the
Read Response would overrun the sink buffer.

This is the second receive-path length fix for this file. A separate
change rejects an MPA FPDU length that underflows the per-fragment
remainder in the header decode; that guard does not cover this case,
because here each individual segment length is self-consistent and only
the accumulated placement offset overruns the buffer.

Published: 2026-07-25

Score: 9.8 Critical

EPSS: < 1% Very Low

KEV: No

Impact:

Action:

Analysis

Impact

A kernel bug in the RDMA/siw read‑response handling allows a connected peer to send read‑response segments that extend beyond the allocated sink buffer because the cumulative offset is not checked on continuation fragments. The resulting out‑of‑bounds memory write can corrupt kernel memory, potentially leading to privilege escalation, arbitrary code execution, or kernel panic. This flaw corresponds to CWE‑787.

Affected Systems

The vulnerability affects the Linux kernel; no specific version range is listed in the CVE data, so any kernel build that does not incorporate the patch is considered vulnerable.

Risk and Exploitability

The EPSS score is reported as less than 1 %, indicating a very low but non‑zero likelihood of exploitation, and the vulnerability is not currently listed in the CISA KEV catalog. However, the flaw can be triggered by an attacker who can open an RDMA connection as the remote peer, requiring no local privilege. Given the high impact of a kernel memory corruption, the risk remains significant for exposed RDMA services.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Linux

unaffected

Version	Status	Constraints
`8b6a361b8c482f22ac99c3273285ff16b23fba91`	affected	< a31b6d18ded3cc32d9ee85a6ff0726d4274887b2
`8b6a361b8c482f22ac99c3273285ff16b23fba91`	affected	< 595e6537ad1a210da32cbb9a7f91aa73090915ba
`8b6a361b8c482f22ac99c3273285ff16b23fba91`	affected	< 3ef7e052cbd05a8b13a51a07b185a39ec93ee1cf
`8b6a361b8c482f22ac99c3273285ff16b23fba91`	affected	< b2e26c955f8dd7e8d3f16c858db05245ea4fa817
`8b6a361b8c482f22ac99c3273285ff16b23fba91`	affected	< 6bc89f34a4597f9f6d41f7a60c67a3153bfe8851
`8b6a361b8c482f22ac99c3273285ff16b23fba91`	affected	< 423a78ff7928c2601013f73ec6d896f5597d0df5
`8b6a361b8c482f22ac99c3273285ff16b23fba91`	affected	< 75c93cd3c421890f49ea93f0b978b9b7bb10e5e3
`8b6a361b8c482f22ac99c3273285ff16b23fba91`	affected	< 7d29f7e9dbd844cae4d3e559cf78324b9642fd6b

Linux

affected

Version	Status	Constraints
`5.3`	affected	—
`0`	unaffected	< 5.3
`5.10.261`	unaffected	≤ 5.10.*
`5.15.212`	unaffected	≤ 5.15.*
`6.1.178`	unaffected	≤ 6.1.*
`6.6.145`	unaffected	≤ 6.6.*
`6.12.96`	unaffected	≤ 6.12.*
`6.18.39`	unaffected	≤ 6.18.*
`7.1.4`	unaffected	≤ 7.1.*
`7.2-rc1`	unaffected	≤ *

Configuration 1 [-]

OR	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::

No data.

Vendor Product Confidence Versions

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`[8b6a361b8c482f22ac99c3273285ff16b23fba91,a31b6d18ded3cc32d9ee85a6ff0726d4274887b2)`	affected	code_commit	—
`[8b6a361b8c482f22ac99c3273285ff16b23fba91,595e6537ad1a210da32cbb9a7f91aa73090915ba)`	affected	code_commit	—
`[8b6a361b8c482f22ac99c3273285ff16b23fba91,3ef7e052cbd05a8b13a51a07b185a39ec93ee1cf)`	affected	code_commit	—
`[8b6a361b8c482f22ac99c3273285ff16b23fba91,b2e26c955f8dd7e8d3f16c858db05245ea4fa817)`	affected	code_commit	—
`[8b6a361b8c482f22ac99c3273285ff16b23fba91,6bc89f34a4597f9f6d41f7a60c67a3153bfe8851)`	affected	code_commit	—
`[8b6a361b8c482f22ac99c3273285ff16b23fba91,423a78ff7928c2601013f73ec6d896f5597d0df5)`	affected	code_commit	—
`[8b6a361b8c482f22ac99c3273285ff16b23fba91,75c93cd3c421890f49ea93f0b978b9b7bb10e5e3)`	affected	code_commit	—
`[8b6a361b8c482f22ac99c3273285ff16b23fba91,7d29f7e9dbd844cae4d3e559cf78324b9642fd6b)`	affected	code_commit	—

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`5.3`	affected	generic	—
`[0,5.3)`	unaffected	generic	—
`[5.10.261,5.11.0)`	unaffected	semver	—
`[5.15.212,5.16.0)`	unaffected	semver	—
`[6.1.178,6.2.0)`	unaffected	semver	—
`[6.6.145,6.7.0)`	unaffected	semver	—
`[6.12.96,6.13.0)`	unaffected	semver	—
`[6.18.39,6.19.0)`	unaffected	semver	—
`[7.1.4,7.2.0)`	unaffected	semver	—
`[7.2-rc1,*]`	unaffected	generic	—

Found an issue or want to improve our Enrichment? You can suggest it directly by opening an issue on our dedicated GitHub repository .

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

Upgrade the Linux kernel to a release that contains the fix for the RDMA/siw read‑response placement bug.
If an immediate kernel upgrade is not feasible, disable the siw RDMA module or restrict RDMA traffic to trusted hosts to limit the attack surface.
Enable kernel audit logs or intrusion detection rules that flag out‑of‑bounds writes or RDMA‑related memory corruption events to detect exploitation attempts.

Generated by OpenCVE AI on August 2, 2026 at 13:41 UTC.

Tracking

Sign in to view the affected projects.

Advisories

Source	ID	Title
Debian DLA	DLA-4717-1	linux security update
Debian DLA	DLA-4720-1	linux security update
Debian DLA	DLA-4723-1	linux-6.1 security update
Debian DLA	DLA-4724-1	linux-6.12 new package

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00695.

Key SSVC decision points have not yet been added.

References

Link	Providers
https://git.kernel.org/stable/c/3ef7e052cbd05a8b13a51a07b185a39ec93ee1cf
https://git.kernel.org/stable/c/423a78ff7928c2601013f73ec6d896f5597d0df5
https://git.kernel.org/stable/c/595e6537ad1a210da32cbb9a7f91aa73090915ba
https://git.kernel.org/stable/c/6bc89f34a4597f9f6d41f7a60c67a3153bfe8851
https://git.kernel.org/stable/c/75c93cd3c421890f49ea93f0b978b9b7bb10e5e3
https://git.kernel.org/stable/c/7d29f7e9dbd844cae4d3e559cf78324b9642fd6b
https://git.kernel.org/stable/c/a31b6d18ded3cc32d9ee85a6ff0726d4274887b2
https://git.kernel.org/stable/c/b2e26c955f8dd7e8d3f16c858db05245ea4fa817
https://lore.kernel.org/linux-cve-announce/2026072559-CVE-2026-64268-629a@gregkh/T
https://nvd.nist.gov/vuln/detail/CVE-2026-64268
https://www.cve.org/CVERecord?id=CVE-2026-64268

History

Sat, 01 Aug 2026 02:45:00 +0000

Type	Values Removed	Values Added
Weaknesses	CWE-119

Thu, 30 Jul 2026 00:15:00 +0000

Type	Values Removed	Values Added
References		https://lore.kernel.org/linux-cve-announce/2026072559-CVE-2026-64268-629a@gregkh/T https://nvd.nist.gov/vuln/detail/CVE-2026-64268 https://www.cve.org/CVERecord?id=CVE-2026-64268
Metrics	threat_severity `None`	threat_severity `Important`

Mon, 27 Jul 2026 05:15:00 +0000

Type	Values Removed	Values Added
Metrics		cvssV3_1 `{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}`

Sun, 26 Jul 2026 03:00:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-119 CWE-787

Sat, 25 Jul 2026 09:30:00 +0000

Type	Values Removed	Values Added
Description		In the Linux kernel, the following vulnerability has been resolved: RDMA/siw: bound Read Response placement to the RREAD length In drivers/infiniband/sw/siw/siw_qp_rx.c, siw_proc_rresp() places each inbound Read Response DDP segment at sge->laddr + wqe->processed and then accumulates wqe->processed, but it never checks the running total against the sink buffer length on continuation segments. siw_check_sge() resolves and validates the sink memory only on the first fragment (the if (!*mem) branch), and siw_rresp_check_ntoh() compares the cumulative length against wqe->bytes only on the final segment (the !frx->more_ddp_segs guard). A connected siw peer that answers an outstanding RREAD with Read Response segments that keep the DDP Last flag clear, carrying more total payload than the RREAD requested, drives wqe->processed past the validated sink buffer; the next siw_rx_data() call writes out of bounds at sge->laddr + wqe->processed. siw runs iWARP over ordinary routable TCP, so the peer is the remote end of an established RDMA connection and needs no local privilege. Bound every segment before placement, exactly as siw_proc_send() and siw_proc_write() already do for their tagged and untagged paths, and terminate the connection with a base-or-bounds DDP error when the Read Response would overrun the sink buffer. This is the second receive-path length fix for this file. A separate change rejects an MPA FPDU length that underflows the per-fragment remainder in the header decode; that guard does not cover this case, because here each individual segment length is self-consistent and only the accumulated placement offset overruns the buffer.
Title		RDMA/siw: bound Read Response placement to the RREAD length
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/3ef7e052cbd05a8b13a51a07b185a39ec93ee1cf https://git.kernel.org/stable/c/423a78ff7928c2601013f73ec6d896f5597d0df5 https://git.kernel.org/stable/c/595e6537ad1a210da32cbb9a7f91aa73090915ba https://git.kernel.org/stable/c/6bc89f34a4597f9f6d41f7a60c67a3153bfe8851 https://git.kernel.org/stable/c/75c93cd3c421890f49ea93f0b978b9b7bb10e5e3 https://git.kernel.org/stable/c/7d29f7e9dbd844cae4d3e559cf78324b9642fd6b https://git.kernel.org/stable/c/a31b6d18ded3cc32d9ee85a6ff0726d4274887b2 https://git.kernel.org/stable/c/b2e26c955f8dd7e8d3f16c858db05245ea4fa817

Subscriptions

Linux Linux Kernel

MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2026-07-25T08:49:16.336Z

Updated: 2026-08-05T12:40:25.712Z

Reserved: 2026-07-19T15:36:31.775Z

Link: CVE-2026-64268

Vulnrichment

No data.

NVD

Status : Analyzed

Published: 2026-07-25T10:17:07.013

Modified: 2026-08-12T15:51:41.393

Link: CVE-2026-64268

Redhat

Severity : Important

Publid Date: 2026-07-25T00:00:00Z

Links: CVE-2026-64268 - Bugzilla

OpenCVE Enrichment

Updated: 2026-08-02T13:45:06Z

Weaknesses

CWE-787
Out-of-bounds Write

Impact

Affected Systems

Risk and Exploitability

Tracking

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

Subscriptions

JSON object

JSON object

JSON object

JSON object

JSON object