bonding: refuse to enslave CAN devices

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-63990
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-19 16:17:18 UTC
Updated2026-07-19 16:17:18 UTC
DescriptionIn 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.

Risk And Classification

EPSS: 0.001810000 probability, percentile 0.078870000 (date 2026-07-20)

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected cd05acfe65ed2cf2db683fa9a6adb8d35635263b 69b78b5f3033272e53a2dc2dad675962654a5b38 git Not specified
CNA Linux Linux affected cd05acfe65ed2cf2db683fa9a6adb8d35635263b 41e8478c4cd896d3abbe33d41afc90c84ac66602 git Not specified
CNA Linux Linux affected cd05acfe65ed2cf2db683fa9a6adb8d35635263b f4d78a81f57df82e9d82a2c07471fed1a1235893 git Not specified
CNA Linux Linux affected cd05acfe65ed2cf2db683fa9a6adb8d35635263b 02f1c87ded33b43d48b4a1d665da15f2157b30d8 git Not specified
CNA Linux Linux affected cd05acfe65ed2cf2db683fa9a6adb8d35635263b 9ea8a648d9120f7652bcde1ce2c4ad66871af707 git Not specified
CNA Linux Linux affected cd05acfe65ed2cf2db683fa9a6adb8d35635263b 563090e5d450c665f70d955a39f9587afc7842eb git Not specified
CNA Linux Linux affected cd05acfe65ed2cf2db683fa9a6adb8d35635263b 8ba68464e4787b6a7ec938826e16124df20fd23d git Not specified
CNA Linux Linux affected 2.6.25 Not specified
CNA Linux Linux unaffected 2.6.25 semver Not specified
CNA Linux Linux unaffected 5.15.210 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.176 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.143 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.93 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.35 6.18.* semver Not specified
CNA Linux Linux unaffected 7.0.12 7.0.* semver Not specified
CNA Linux Linux unaffected 7.1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/41e8478c4cd896d3abbe33d41afc90c84ac66602 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/8ba68464e4787b6a7ec938826e16124df20fd23d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/02f1c87ded33b43d48b4a1d665da15f2157b30d8 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/563090e5d450c665f70d955a39f9587afc7842eb 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/9ea8a648d9120f7652bcde1ce2c4ad66871af707 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/f4d78a81f57df82e9d82a2c07471fed1a1235893 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/69b78b5f3033272e53a2dc2dad675962654a5b38 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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