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NVD / CVE Program· CNA Linux

CVE-2026-63996: ethtool: cmis: require exact CDB reply length

Noroxi assessment

Priority: Monitor (action score 31/100)

  • 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: 0.12% (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 2f818cc98fd2c63a08239cb48995f6c3bfe9d9b3, 4d42fb88ec61f2e98c33a9e3a2de371d5edbc6b1, 6c3f999a9d1338c6c89a9ff4549eafe72bc2e7b1.

Low priority for now. Upgrade to Linux Linux 2f818cc98fd2c63a08239cb48995f6c3bfe9d9b3, 4d42fb88ec61f2e98c33a9e3a2de371d5edbc6b1, 6c3f999a9d1338c6c89a9ff4549eafe72bc2e7b1 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: ethtool: cmis: require exact CDB reply length Malicious SFP module could respond with rpl_len longer than what cmis_cdb_process_reply() expected, leading to OOB writes. Malicious HW is a bit theoretical but some modules may just be buggy and/or the reads may occasionally get corrupted, so let's protect the kernel. The existing check protects from short replies. We need to protect from long ones, too. All callers that pass a non-zero rpl_exp_len cast the reply payload to a fixed-layout struct and read fields at fixed offsets, with no version negotiation or short-reply handling: - cmis_cdb_validate_password() - cmis_cdb_module_features_get() - cmis_fw_update_fw_mng_features_get() so let's assume that responses longer than expected do not have to be handled gracefully here. Add a warning message to make the debug easier in case my understanding is wrong... Note that page_data->length (argument of kmalloc) comes from last arg to ethtool_cmis_page_init() which is rpl_exp_len. Note2 that AIs also like to point out overflows in args->req.payload itself (which is a fixed-size 120 B buffer, on the stack), but callers should be reading structs defined by the standard, so protecting from requests for more data than max seem like defensive programming.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Jul 19, 2026
Updated
Oct 19, 2026
EPSS
0.1% · 2th percentile

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
7.8
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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  • 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 kernel6.11 and later · before 6.12.93
  • linux linux kernel6.13 and later · before 6.18.35
  • linux linux kernel6.19 and later · before 7.0.12
  • linux linux kernel7.1

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

    • 6.11affected
    • a39c84d796254e6b1662ca0c46dbc313379e9291 and later · before 2f818cc98fd2c63a08239cb48995f6c3bfe9d9b3affected · git
    • a39c84d796254e6b1662ca0c46dbc313379e9291 and later · before 4d42fb88ec61f2e98c33a9e3a2de371d5edbc6b1affected · git
    • a39c84d796254e6b1662ca0c46dbc313379e9291 and later · before eb5dcd740cd7fa27bc2caeff2d28ef28e93ff4d3affected · git
    • a39c84d796254e6b1662ca0c46dbc313379e9291 and later · before 6c3f999a9d1338c6c89a9ff4549eafe72bc2e7b1affected · git
    • before 6.11not affected · semver
    • 6.12.93 and later · up to and including 6.12.*not affected · semver
    • 6.18.35 and later · up to and including 6.18.*not affected · semver
    • 7.0.12 and later · up to and including 7.0.*not affected · semver
    • 7.1 and laternot affected · original_commit_for_fix

Package-level exposure

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

EcosystemPackageAffected rangeFix
AlmaLinux:10kernelbefore 6.12.0-211.73.1.el10_26.12.0-211.73.1.el10_2
AlmaLinux:10kernel-64kbefore 6.12.0-211.73.1.el10_26.12.0-211.73.1.el10_2
AlmaLinux:10kernel-64k-corebefore 6.12.0-211.73.1.el10_26.12.0-211.73.1.el10_2
AlmaLinux:10kernel-64k-debugbefore 6.12.0-211.73.1.el10_26.12.0-211.73.1.el10_2
AlmaLinux:10kernel-64k-debug-corebefore 6.12.0-211.73.1.el10_26.12.0-211.73.1.el10_2
AlmaLinux:10kernel-64k-debug-develbefore 6.12.0-211.73.1.el10_26.12.0-211.73.1.el10_2
AlmaLinux:10kernel-64k-debug-devel-matchedbefore 6.12.0-211.73.1.el10_26.12.0-211.73.1.el10_2
AlmaLinux:10kernel-64k-debug-modulesbefore 6.12.0-211.73.1.el10_26.12.0-211.73.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-corebefore 6.12.0-211.73.1.el10_26.12.0-211.73.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-extrabefore 6.12.0-211.73.1.el10_26.12.0-211.73.1.el10_2
AlmaLinux:10kernel-64k-develbefore 6.12.0-211.73.1.el10_26.12.0-211.73.1.el10_2
AlmaLinux:10kernel-64k-devel-matchedbefore 6.12.0-211.73.1.el10_26.12.0-211.73.1.el10_2
AlmaLinux:10kernel-64k-modulesbefore 6.12.0-211.73.1.el10_26.12.0-211.73.1.el10_2
AlmaLinux:10kernel-64k-modules-corebefore 6.12.0-211.73.1.el10_26.12.0-211.73.1.el10_2
AlmaLinux:10kernel-64k-modules-extrabefore 6.12.0-211.73.1.el10_26.12.0-211.73.1.el10_2
AlmaLinux:10kernel-abi-stablelistsbefore 6.12.0-211.73.1.el10_26.12.0-211.73.1.el10_2
AlmaLinux:10kernel-corebefore 6.12.0-211.73.1.el10_26.12.0-211.73.1.el10_2
AlmaLinux:10kernel-cross-headersbefore 6.12.0-211.73.1.el10_26.12.0-211.73.1.el10_2
AlmaLinux:10kernel-debugbefore 6.12.0-211.73.1.el10_26.12.0-211.73.1.el10_2
AlmaLinux:10kernel-debug-corebefore 6.12.0-211.73.1.el10_26.12.0-211.73.1.el10_2
AlmaLinux:10kernel-debug-develbefore 6.12.0-211.73.1.el10_26.12.0-211.73.1.el10_2
AlmaLinux:10kernel-debug-devel-matchedbefore 6.12.0-211.73.1.el10_26.12.0-211.73.1.el10_2
AlmaLinux:10kernel-debug-modulesbefore 6.12.0-211.73.1.el10_26.12.0-211.73.1.el10_2
AlmaLinux:10kernel-debug-modules-corebefore 6.12.0-211.73.1.el10_26.12.0-211.73.1.el10_2

+86

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-2026-63994Jul 19, 2026 · tunnels: load network headers after skb_cow() in iptunnel_pmtud_build_icmp[v6]()
    39Monitor
  • ← EarlierCVE-2026-63995Jul 19, 2026 · ethtool: cmis: validate start_cmd_payload_size from module
    31Monitor
  • Later →CVE-2026-63997Jul 19, 2026 · ethtool: module: avoid leaking a netdev ref on module flash errors
    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 Linux2f818cc98fd2c63a08239cb48995f6c3bfe9d9b3Vendor (CNA)
Linux Linux4d42fb88ec61f2e98c33a9e3a2de371d5edbc6b1Vendor (CNA)
Linux Linux6c3f999a9d1338c6c89a9ff4549eafe72bc2e7b1Vendor (CNA)
Linux Linuxeb5dcd740cd7fa27bc2caeff2d28ef28e93ff4d3Vendor (CNA)
almalinux:kernel6.12.0-211.73.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k6.12.0-211.73.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-core6.12.0-211.73.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug6.12.0-211.73.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-core6.12.0-211.73.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-devel6.12.0-211.73.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-devel-matched6.12.0-211.73.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules6.12.0-211.73.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules-core6.12.0-211.73.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules-extra6.12.0-211.73.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-devel6.12.0-211.73.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-devel-matched6.12.0-211.73.1.el10_2 · AlmaLinux:10Package registry (OSV)
debian:linux6.12.94-1 · Debian:13Package registry (OSV)
rocky linux:kernel0:6.12.0-211.73.1.el10_2 · Rocky Linux:10Package 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).

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
high · data or configuration can be modified
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
High
Availability impact
High

Weakness class (CWE)

CWE-787 · Out-of-bounds Write

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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. SSVC exploitation— → none
  2. Fix✗ → ✓

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

References

Show all references (3 more)

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

All records