{"id":"CVE-2026-63990","state":"PUBLISHED","title":"bonding: refuse to enslave CAN devices","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbonding: refuse to enslave CAN devices\n\nsyzbot reported a kernel paging request crash in\ncan_rx_unregister() inside net/can/af_can.c. The crash occurs\nbecause a virtual CAN device (vxcan) is being enslaved to a\nbonding master.\n\nDuring the enslavement process, the bonding driver mutates\nand modifies the network device states to fit an Ethernet-like\naggregation model. However, CAN devices operate on a completely\ndifferent Layer 2 architecture, relying on the CAN mid-layer\nprivate data structure (can_ml_priv) instead of standard\nEthernet structures. Since bonding does not initialize or\nmaintain these CAN structures, subsequent operations on the\nhalf-enslaved interface (such as closing associated sockets\nvia isotp_release) lead to a null-pointer dereference when\naccessing the CAN receiver lists.\n\nBonding CAN interfaces is architecturally invalid as CAN lacks\nMAC addresses, ARP capabilities, and standard Ethernet\nlink-layer mechanisms. While generic loopback devices are\nblocked globally in net/core/dev.c, virtual CAN devices\nbypass this check because they do not carry the IFF_LOOPBACK\nflag, despite acting as local software-loopbacks.\n\nFix this by explicitly blocking network devices of type\nARPHRD_CAN from being enslaved at the very beginning of\nbond_enslave(). This prevents illegal state mutations,\neliminates the resulting KASAN crashes, and avoids potential\nmemory leaks from incomplete socket cleanups.\n\nAs the CAN support has been added a long time after bonding\nthe Fixes-tag points to the introduction of ARPHRD_CAN that\nwould have needed a specific handling in bonding_main.c.","publishedAt":"2026-07-19T14:56:11.111Z","updatedAt":"2026-07-19T14:56:11.111Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"cd05acfe65ed2cf2db683fa9a6adb8d35635263b","status":"affected","lessThan":"69b78b5f3033272e53a2dc2dad675962654a5b38","versionType":"git"},{"version":"cd05acfe65ed2cf2db683fa9a6adb8d35635263b","status":"affected","lessThan":"41e8478c4cd896d3abbe33d41afc90c84ac66602","versionType":"git"},{"version":"cd05acfe65ed2cf2db683fa9a6adb8d35635263b","status":"affected","lessThan":"f4d78a81f57df82e9d82a2c07471fed1a1235893","versionType":"git"},{"version":"cd05acfe65ed2cf2db683fa9a6adb8d35635263b","status":"affected","lessThan":"02f1c87ded33b43d48b4a1d665da15f2157b30d8","versionType":"git"},{"version":"cd05acfe65ed2cf2db683fa9a6adb8d35635263b","status":"affected","lessThan":"9ea8a648d9120f7652bcde1ce2c4ad66871af707","versionType":"git"},{"version":"cd05acfe65ed2cf2db683fa9a6adb8d35635263b","status":"affected","lessThan":"563090e5d450c665f70d955a39f9587afc7842eb","versionType":"git"},{"version":"cd05acfe65ed2cf2db683fa9a6adb8d35635263b","status":"affected","lessThan":"8ba68464e4787b6a7ec938826e16124df20fd23d","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/bonding/bond_main.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.25","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.25","versionType":"semver"},{"version":"5.15.210","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.176","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.143","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.93","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.35","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.12","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/bonding/bond_main.c"]}],"references":["https://git.kernel.org/stable/c/69b78b5f3033272e53a2dc2dad675962654a5b38","https://git.kernel.org/stable/c/41e8478c4cd896d3abbe33d41afc90c84ac66602","https://git.kernel.org/stable/c/f4d78a81f57df82e9d82a2c07471fed1a1235893","https://git.kernel.org/stable/c/02f1c87ded33b43d48b4a1d665da15f2157b30d8","https://git.kernel.org/stable/c/9ea8a648d9120f7652bcde1ce2c4ad66871af707","https://git.kernel.org/stable/c/563090e5d450c665f70d955a39f9587afc7842eb","https://git.kernel.org/stable/c/8ba68464e4787b6a7ec938826e16124df20fd23d"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/63xxx/CVE-2026-63990.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-63990","state":"PUBLISHED","datePublished":"2026-07-19T14:56:11.111Z","dateUpdated":"2026-07-19T14:56:11.111Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-19T07:54:57.025Z"},"containers":{"cna":{"title":"bonding: refuse to enslave CAN devices","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nbonding: refuse to enslave CAN devices\n\nsyzbot reported a kernel paging request crash in\ncan_rx_unregister() inside net/can/af_can.c. The crash occurs\nbecause a virtual CAN device (vxcan) is being enslaved to a\nbonding master.\n\nDuring the enslavement process, the bonding driver mutates\nand modifies the network device states to fit an Ethernet-like\naggregation model. However, CAN devices operate on a completely\ndifferent Layer 2 architecture, relying on the CAN mid-layer\nprivate data structure (can_ml_priv) instead of standard\nEthernet structures. Since bonding does not initialize or\nmaintain these CAN structures, subsequent operations on the\nhalf-enslaved interface (such as closing associated sockets\nvia isotp_release) lead to a null-pointer dereference when\naccessing the CAN receiver lists.\n\nBonding CAN interfaces is architecturally invalid as CAN lacks\nMAC addresses, ARP capabilities, and standard Ethernet\nlink-layer mechanisms. While generic loopback devices are\nblocked globally in net/core/dev.c, virtual CAN devices\nbypass this check because they do not carry the IFF_LOOPBACK\nflag, despite acting as local software-loopbacks.\n\nFix this by explicitly blocking network devices of type\nARPHRD_CAN from being enslaved at the very beginning of\nbond_enslave(). This prevents illegal state mutations,\neliminates the resulting KASAN crashes, and avoids potential\nmemory leaks from incomplete socket cleanups.\n\nAs the CAN support has been added a long time after bonding\nthe Fixes-tag points to the introduction of ARPHRD_CAN that\nwould have needed a specific handling in bonding_main.c."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"cd05acfe65ed2cf2db683fa9a6adb8d35635263b","status":"affected","lessThan":"69b78b5f3033272e53a2dc2dad675962654a5b38","versionType":"git"},{"version":"cd05acfe65ed2cf2db683fa9a6adb8d35635263b","status":"affected","lessThan":"41e8478c4cd896d3abbe33d41afc90c84ac66602","versionType":"git"},{"version":"cd05acfe65ed2cf2db683fa9a6adb8d35635263b","status":"affected","lessThan":"f4d78a81f57df82e9d82a2c07471fed1a1235893","versionType":"git"},{"version":"cd05acfe65ed2cf2db683fa9a6adb8d35635263b","status":"affected","lessThan":"02f1c87ded33b43d48b4a1d665da15f2157b30d8","versionType":"git"},{"version":"cd05acfe65ed2cf2db683fa9a6adb8d35635263b","status":"affected","lessThan":"9ea8a648d9120f7652bcde1ce2c4ad66871af707","versionType":"git"},{"version":"cd05acfe65ed2cf2db683fa9a6adb8d35635263b","status":"affected","lessThan":"563090e5d450c665f70d955a39f9587afc7842eb","versionType":"git"},{"version":"cd05acfe65ed2cf2db683fa9a6adb8d35635263b","status":"affected","lessThan":"8ba68464e4787b6a7ec938826e16124df20fd23d","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/bonding/bond_main.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.25","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.25","versionType":"semver"},{"version":"5.15.210","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.176","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.143","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.93","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.35","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.12","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/bonding/bond_main.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/69b78b5f3033272e53a2dc2dad675962654a5b38"},{"url":"https://git.kernel.org/stable/c/41e8478c4cd896d3abbe33d41afc90c84ac66602"},{"url":"https://git.kernel.org/stable/c/f4d78a81f57df82e9d82a2c07471fed1a1235893"},{"url":"https://git.kernel.org/stable/c/02f1c87ded33b43d48b4a1d665da15f2157b30d8"},{"url":"https://git.kernel.org/stable/c/9ea8a648d9120f7652bcde1ce2c4ad66871af707"},{"url":"https://git.kernel.org/stable/c/563090e5d450c665f70d955a39f9587afc7842eb"},{"url":"https://git.kernel.org/stable/c/8ba68464e4787b6a7ec938826e16124df20fd23d"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-07-19T14:56:11.111Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.25","versionEndExcluding":"5.15.210"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.25","versionEndExcluding":"6.1.176"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.25","versionEndExcluding":"6.6.143"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.25","versionEndExcluding":"6.12.93"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.25","versionEndExcluding":"6.18.35"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.25","versionEndExcluding":"7.0.12"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.25","versionEndExcluding":"7.1"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}