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NVD / CVE Program· CNA Linux

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

Noroxi assessment

Priority: Monitor (action score 36/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.71% (FIRST EPSS); higher than 53.9% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 2912f3d40355dabc08fdbaaf2764d02445fe88dc, 5a45d0aa1fa50a333ce5763ade744e2d89838667, 68c09762172f6224e9ddf9b0a60bacbb36e443eb; azl3 kernel 6.6.144.1-1 on Azure Linux 3.0 6.6.145.2-1.

Low priority for now. Upgrade to Linux Linux 2912f3d40355dabc08fdbaaf2764d02445fe88dc, 5a45d0aa1fa50a333ce5763ade744e2d89838667, 68c09762172f6224e9ddf9b0a60bacbb36e443eb; azl3 kernel 6.6.144.1-1 on Azure Linux 3.0 6.6.145.2-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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).

CriticalCVSS 9.1 · v3.1—No exploit Fix available
Published
Jul 25, 2026
Updated
Aug 23, 2026
EPSS
0.7% · 53th percentile
CWE
—

Report tools

JSON

Action score

36

Monitor

Low priority for now.

CVSS
36 / 40 · 9.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.7%

CNA vs NVD score

NVD
—
CNA · Linux
9.1
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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When you'll hear from us

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  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel5.8 and later · before 5.15.212
  • linux linux kernel5.16 and later · before 6.1.178
  • linux linux kernel6.2 and later · before 6.6.145
  • linux linux kernel6.7 and later · before 6.12.96
  • linux linux kernel6.13 and later · before 6.18.39
  • linux linux kernel6.19 and later · before 7.1.4

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.8affected
    • 9cb837480424e78ed585376f944088246685aec3 and later · before a35b7a8728a53ddc80b323970689fa5985816836affected · git
    • 9cb837480424e78ed585376f944088246685aec3 and later · before 68c09762172f6224e9ddf9b0a60bacbb36e443ebaffected · git
    • 9cb837480424e78ed585376f944088246685aec3 and later · before 6cada540150894e81042a0ae0c796a21a9a877daaffected · git
    • 9cb837480424e78ed585376f944088246685aec3 and later · before 2912f3d40355dabc08fdbaaf2764d02445fe88dcaffected · git
    • 9cb837480424e78ed585376f944088246685aec3 and later · before 6f40246f4312fdbab5a13cc440adebf95eb2aa66affected · git
    • 9cb837480424e78ed585376f944088246685aec3 and later · before 5a45d0aa1fa50a333ce5763ade744e2d89838667affected · git
    • 9cb837480424e78ed585376f944088246685aec3 and later · before da3e44add94b05dfde56f898421922f5cf35705faffected · git
    • 9cb837480424e78ed585376f944088246685aec3 and later · before 963af8d97a8c6a117134a8d0db1415e0489200b1affected · git
    • before 5.8not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.180-16.1.180-1
Debian:12linux-6.12before 6.12.100-1~deb12u16.12.100-1~deb12u1
Debian:13linuxbefore 6.12.96-16.12.96-1
Debian:14linuxbefore 7.1.4-17.1.4-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-64265Jul 25, 2026 · fuse: clear intr_entry in fuse_resend and fuse_remove_pending_req
    31Monitor
  • ← EarlierCVE-2026-64267Jul 25, 2026 · fuse: avoid 32-bit prune notification count wrap
    22Monitor
  • Later →CVE-2026-64278Jul 25, 2026 · i2c: imx-lpi2c: mark I2C adapter when hardware is powered down
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux2912f3d40355dabc08fdbaaf2764d02445fe88dcVendor (CNA)
Linux Linux5a45d0aa1fa50a333ce5763ade744e2d89838667Vendor (CNA)
Linux Linux68c09762172f6224e9ddf9b0a60bacbb36e443ebVendor (CNA)
Linux Linux6cada540150894e81042a0ae0c796a21a9a877daVendor (CNA)
Linux Linux6f40246f4312fdbab5a13cc440adebf95eb2aa66Vendor (CNA)
Linux Linux963af8d97a8c6a117134a8d0db1415e0489200b1Vendor (CNA)
Linux Linuxa35b7a8728a53ddc80b323970689fa5985816836Vendor (CNA)
Linux Linuxda3e44add94b05dfde56f898421922f5cf35705fVendor (CNA)
azl3 kernel 6.6.144.1-1 on Azure Linux 3.06.6.145.2-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.180-1 · Debian:12Package registry (OSV)
debian:linux-6.126.12.100-1~deb12u1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days+1% in 7 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
None
Availability impact
High

Weakness class (CWE)

—

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records