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NVD / CVE Program· CNA Linux

CVE-2026-64055: net: ethernet: cortina: Carry over frag counter

Noroxi assessment

Priority: Monitor (action score 39/100)

  • 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: 0.51% (FIRST EPSS).
  • 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 46806096f35b8d3dfa2f321ddd77f597edcdb85f, 7123cf481e21b54eb6adc4cb0d8dc2876aeaee41, 75105fcf73f1ce7d9f769aaefec6e6d6645d5ac0.

Low priority for now. Upgrade to Linux Linux 46806096f35b8d3dfa2f321ddd77f597edcdb85f, 7123cf481e21b54eb6adc4cb0d8dc2876aeaee41, 75105fcf73f1ce7d9f769aaefec6e6d6645d5ac0 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: net: ethernet: cortina: Carry over frag counter The gmac_rx() NAPI poll function assembles packets in an SKB from a ring buffer. If the ring buffer gets completely emptied during a poll cycle, we exit gmac_rx(), but the packet is not yet completely assembled in the SKB, yet the fragment counter frag_nr is reset to zero on the next invocation. Solve this by making the RX fragment counter a part of the port struct, and carry it over between invocations. Reset the fragment counter only right after calling napi_gro_frags(), on error (after calling napi_free_frags()) or if stopping the port. Reset it in some place where not strictly necessary just to emphasize what is going on. This was found by Sashiko during normal patch review.

CriticalCVSS 9.8 · v3.1—No exploit Fix available
Published
Jul 19, 2026
Updated
Sep 2, 2026
EPSS
0.5% · 43th percentile
CWE
—

Report tools

JSON

Action score

39

Monitor

Low priority for now.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CNA vs NVD score

NVD
—
CNA · Linux
9.8
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.

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

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-64055

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • 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 kernel4.16 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 6.6.142
  • linux linux kernel6.7 and later · before 6.12.92
  • linux linux kernel6.13 and later · before 6.18.34
  • linux linux kernel6.19 and later · before 7.0.11
  • 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

    • 4.16affected
    • 4d5ae32f5e1e13f7f36d6439ec3257993b9f5b88 and later · before df31e3b64455293df1ea89c7da7d5c9bfbcdd253affected · git
    • 4d5ae32f5e1e13f7f36d6439ec3257993b9f5b88 and later · before 7af1fabdee744b7995fe01b30b77dfc397657cb5affected · git
    • 4d5ae32f5e1e13f7f36d6439ec3257993b9f5b88 and later · before 75105fcf73f1ce7d9f769aaefec6e6d6645d5ac0affected · git
    • 4d5ae32f5e1e13f7f36d6439ec3257993b9f5b88 and later · before 78cf08b3be47c28f07008a76c932bad7cdffa9d8affected · git
    • 4d5ae32f5e1e13f7f36d6439ec3257993b9f5b88 and later · before 7123cf481e21b54eb6adc4cb0d8dc2876aeaee41affected · git
    • 4d5ae32f5e1e13f7f36d6439ec3257993b9f5b88 and later · before c373b34877afea61c89e0dd2e38948c624249b9baffected · git
    • 4d5ae32f5e1e13f7f36d6439ec3257993b9f5b88 and later · before 46806096f35b8d3dfa2f321ddd77f597edcdb85faffected · git
    • 4d5ae32f5e1e13f7f36d6439ec3257993b9f5b88 and later · before ebd8ec2b309e3a447851b456ccaf8fb39f3661e7affected · git
    • before 4.16not 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 6.12.94-16.12.94-1
Debian:14linuxbefore 7.0.12-17.0.12-1

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-2026-64052Jul 19, 2026 · block: bio-integrity: Fix null-ptr-deref in bio_integrity_map_user()
    22Monitor
  • ← EarlierCVE-2026-64054Jul 19, 2026 · net: shaper: reject duplicate leaves in GROUP request
    31Monitor
  • Later →CVE-2026-64056Jul 19, 2026 · net: ethernet: cortina: Make RX SKB per-port
    39Monitor

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 Linux46806096f35b8d3dfa2f321ddd77f597edcdb85fVendor (CNA)
Linux Linux7123cf481e21b54eb6adc4cb0d8dc2876aeaee41Vendor (CNA)
Linux Linux75105fcf73f1ce7d9f769aaefec6e6d6645d5ac0Vendor (CNA)
Linux Linux78cf08b3be47c28f07008a76c932bad7cdffa9d8Vendor (CNA)
Linux Linux7af1fabdee744b7995fe01b30b77dfc397657cb5Vendor (CNA)
Linux Linuxc373b34877afea61c89e0dd2e38948c624249b9bVendor (CNA)
Linux Linuxdf31e3b64455293df1ea89c7da7d5c9bfbcdd253Vendor (CNA)
Linux Linuxebd8ec2b309e3a447851b456ccaf8fb39f3661e7Vendor (CNA)
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).

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

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/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. 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