Reference page — cumulative record through Thursday, October 8, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
AV AC PR UI S C I A CVSS EPSS %ile KEV L L L N U N N H 5.5 .0018 7.0 —
AFFECTED Product Versions Fixed Linux cd05acfe65ed2cf2db683fa9a6adb8d35635263b – — Linux 2.6.25 – 5.15.210
TIMELINE Jul 19 Reserved by Linux Jul 19 Published (CNA: Linux) Oct 7 ENRICHED — CVE-2026-63990 (Linux). Received CVSS 5.5 and CPE data from NVD.
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.
| Date | Event | Detail |
|---|---|---|
| July 19, 2026 | Reserved | Reserved by Linux |
| July 19, 2026 | Published | Published (CNA: Linux) |
| October 7, 2026 | ENRICHED | ENRICHED — CVE-2026-63990 (Linux). Received CVSS 5.5 and CPE data from NVD. |
Authoritative record: CVE-2026-63990 at cve.org
Vendors: linux
Weaknesses: CWE-401
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-63990 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Thursday, October 8, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.
