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NVD / CVE Program· CNA Linux

CVE-2026-63990: bonding: refuse to enslave CAN devices

Noroxi assessment

Priority: Monitor (action score 22/100)

  • 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: 0.13% (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 02f1c87ded33b43d48b4a1d665da15f2157b30d8, 41e8478c4cd896d3abbe33d41afc90c84ac66602, 563090e5d450c665f70d955a39f9587afc7842eb.

Low priority for now. Upgrade to Linux Linux 02f1c87ded33b43d48b4a1d665da15f2157b30d8, 41e8478c4cd896d3abbe33d41afc90c84ac66602, 563090e5d450c665f70d955a39f9587afc7842eb 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: bonding: refuse to enslave CAN devices syzbot reported a kernel paging request crash in can_rx_unregister() inside net/can/af_can.c. The crash occurs because a virtual CAN device (vxcan) is being enslaved to a bonding master. During the enslavement process, the bonding driver mutates and modifies the network device states to fit an Ethernet-like aggregation model. However, CAN devices operate on a completely different Layer 2 architecture, relying on the CAN mid-layer private data structure (can_ml_priv) instead of standard Ethernet structures. Since bonding does not initialize or maintain these CAN structures, subsequent operations on the half-enslaved interface (such as closing associated sockets via isotp_release) lead to a null-pointer dereference when accessing the CAN receiver lists. Bonding CAN interfaces is architecturally invalid as CAN lacks MAC addresses, ARP capabilities, and standard Ethernet link-layer mechanisms. While generic loopback devices are blocked globally in net/core/dev.c, virtual CAN devices bypass this check because they do not carry the IFF_LOOPBACK flag, despite acting as local software-loopbacks. Fix this by explicitly blocking network devices of type ARPHRD_CAN from being enslaved at the very beginning of bond_enslave(). This prevents illegal state mutations, eliminates the resulting KASAN crashes, and avoids potential memory leaks from incomplete socket cleanups. As the CAN support has been added a long time after bonding the Fixes-tag points to the introduction of ARPHRD_CAN that would have needed a specific handling in bonding_main.c.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Jul 19, 2026
Updated
Oct 8, 2026
EPSS
0.1% · 2th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 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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When you'll hear from us

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  • when exploit code appears or is weaponized
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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 kernel2.6.25 and later · before 5.15.210
  • linux linux kernel5.16 and later · before 6.1.176
  • linux linux kernel6.2 and later · before 6.6.143
  • linux linux kernel6.7 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

    • 2.6.25affected
    • cd05acfe65ed2cf2db683fa9a6adb8d35635263b and later · before 69b78b5f3033272e53a2dc2dad675962654a5b38affected · git
    • cd05acfe65ed2cf2db683fa9a6adb8d35635263b and later · before 41e8478c4cd896d3abbe33d41afc90c84ac66602affected · git
    • cd05acfe65ed2cf2db683fa9a6adb8d35635263b and later · before f4d78a81f57df82e9d82a2c07471fed1a1235893affected · git
    • cd05acfe65ed2cf2db683fa9a6adb8d35635263b and later · before 02f1c87ded33b43d48b4a1d665da15f2157b30d8affected · git
    • cd05acfe65ed2cf2db683fa9a6adb8d35635263b and later · before 9ea8a648d9120f7652bcde1ce2c4ad66871af707affected · git
    • cd05acfe65ed2cf2db683fa9a6adb8d35635263b and later · before 563090e5d450c665f70d955a39f9587afc7842ebaffected · git
    • cd05acfe65ed2cf2db683fa9a6adb8d35635263b and later · before 8ba68464e4787b6a7ec938826e16124df20fd23daffected · git
    • before 2.6.25not affected · semver
    • 5.15.210 and later · up to and including 5.15.*not 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-2026-63988Jul 19, 2026 · bridge: Fix sleep in atomic context in sysfs path
    22Monitor
  • ← EarlierCVE-2026-63989Jul 19, 2026 · bridge: Fix sleep in atomic context in netlink path
    22Monitor
  • Later →CVE-2026-63991Jul 19, 2026 · Bluetooth: 6lowpan: check skb_clone() return value in send_mcast_pkt()
    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 Linux02f1c87ded33b43d48b4a1d665da15f2157b30d8Vendor (CNA)
Linux Linux41e8478c4cd896d3abbe33d41afc90c84ac66602Vendor (CNA)
Linux Linux563090e5d450c665f70d955a39f9587afc7842ebVendor (CNA)
Linux Linux69b78b5f3033272e53a2dc2dad675962654a5b38Vendor (CNA)
Linux Linux8ba68464e4787b6a7ec938826e16124df20fd23dVendor (CNA)
Linux Linux9ea8a648d9120f7652bcde1ce2c4ad66871af707Vendor (CNA)
Linux Linuxf4d78a81f57df82e9d82a2c07471fed1a1235893Vendor (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

  • 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
none
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
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-476 · NULL Pointer Dereference

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/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.

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

Change log

  1. CVSS— → 5.5
  2. Severity— → medium
  3. Fix✗ → ✓

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

References

Show all references (6 more)

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

All records