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NVD / CVE Program· CNA Linux

CVE-2026-46064: ibmasm: fix heap over-read in ibmasm_send_i2o_message()

Noroxi assessment

Priority: Monitor (action score 28/100)

  • 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: 0.14% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 9aad71144fa3682cca3837a06c8623016790e7ec, 9e8f6c9d4ecddda2f28baa1678340286cff3969c, b870f652877bfbe321bd0f4096fc37a93296f7b6; azl3 kernel 6.6.139.1-1 on Azure Linux 3.0 6.6.141.1-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 9aad71144fa3682cca3837a06c8623016790e7ec, 9e8f6c9d4ecddda2f28baa1678340286cff3969c, b870f652877bfbe321bd0f4096fc37a93296f7b6; azl3 kernel 6.6.139.1-1 on Azure Linux 3.0 6.6.141.1-1 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: ibmasm: fix heap over-read in ibmasm_send_i2o_message() The ibmasm_send_i2o_message() function uses get_dot_command_size() to compute the byte count for memcpy_toio(), but this value is derived from user-controlled fields in the dot_command_header (command_size: u8, data_size: u16) and is never validated against the actual allocation size. A root user can write a small buffer with inflated header fields, causing memcpy_toio() to read up to ~65 KB past the end of the allocation into adjacent kernel heap, which is then forwarded to the service processor over MMIO. Silently clamping the copy size is not sufficient: if the header fields claim a larger size than the buffer, the SP receives a dot command whose own header is inconsistent with the I2O message length, which can cause the SP to desynchronize. Reject such commands outright by returning failure. Validate command_size before calling get_mfa_inbound() to avoid leaking an I2O message frame: reading INBOUND_QUEUE_PORT dequeues a hardware frame from the controller's free pool, and returning without a corresponding set_mfa_inbound() call would permanently exhaust it. Additionally, clamp command_size to I2O_COMMAND_SIZE before the memcpy_toio() so the MMIO write stays within the I2O message frame, consistent with the clamping already performed by outgoing_message_size() for the header field.

HighCVSS 7.1 · v3.1—No exploit Fix available
Published
May 27, 2026
Updated
Oct 15, 2026
EPSS
0.1% · 3th percentile

Report tools

JSON

Action score

28

Monitor

Low priority for now.

CVSS
28 / 40 · 7.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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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 kernel2.6.12.1 and later · before 5.10.258
  • linux linux kernel5.11 and later · before 5.15.209
  • linux linux kernel5.16 and later · before 6.1.175
  • linux linux kernel6.2 and later · before 6.6.140
  • linux linux kernel6.7 and later · before 6.12.86
  • linux linux kernel6.13 and later · before 6.18.27
  • linux linux kernel6.19 and later · before 7.0.4
  • linux linux kernel2.6.12

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

    • 2.6.12affected
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before ca1c857e2bb74a9fc0606128334f85316d57067baffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before b870f652877bfbe321bd0f4096fc37a93296f7b6affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before ce57fa439bd1b5d664f334a0c3e3f0e42abb0153affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before fd19eb1c75047a4ed4e855f56cafd704dc3914e0affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before fe31722b0194ff76bf8b461e8bf97a2081147787affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before c1c2417c60dbdca5ebb00462f21ee71c2d7f7083affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 9e8f6c9d4ecddda2f28baa1678340286cff3969caffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 9aad71144fa3682cca3837a06c8623016790e7ecaffected · git
    • before 2.6.12not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.176-16.1.176-1
Debian:13linuxbefore 6.12.86-16.12.86-1
Debian:14linuxbefore 7.0.4-17.0.4-1

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-2026-46056May 27, 2026 · Bluetooth: hci_event: fix potential UAF in SSP passkey handlers
    35Monitor
  • ← EarlierCVE-2026-46059May 27, 2026 · KVM: nSVM: Always use NextRIP as vmcb02's NextRIP after first L2 VMRUN
    22Monitor
  • Later →CVE-2026-46065May 27, 2026 · fbdev: defio: Disconnect deferred I/O from the lifetime of struct fb_info
    31Monitor

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 Linux9aad71144fa3682cca3837a06c8623016790e7ecVendor (CNA)
Linux Linux9e8f6c9d4ecddda2f28baa1678340286cff3969cVendor (CNA)
Linux Linuxb870f652877bfbe321bd0f4096fc37a93296f7b6Vendor (CNA)
Linux Linuxc1c2417c60dbdca5ebb00462f21ee71c2d7f7083Vendor (CNA)
Linux Linuxca1c857e2bb74a9fc0606128334f85316d57067bVendor (CNA)
Linux Linuxce57fa439bd1b5d664f334a0c3e3f0e42abb0153Vendor (CNA)
Linux Linuxfd19eb1c75047a4ed4e855f56cafd704dc3914e0Vendor (CNA)
Linux Linuxfe31722b0194ff76bf8b461e8bf97a2081147787Vendor (CNA)
azl3 kernel 6.6.139.1-1 on Azure Linux 3.06.6.141.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.176-1 · 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

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).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • 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
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-125 · Out-of-bounds Read

CVSS vector

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

nvd-primary

Attack context

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

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

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

References

Show all references (8 more)

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

All records