{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-39986","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2025-04-16T07:20:57.150Z","datePublished":"2025-10-15T07:56:05.143Z","dateUpdated":"2026-05-11T21:40:15.706Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-05-11T21:40:15.706Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ncan: sun4i_can: populate ndo_change_mtu() to prevent buffer overflow\n\nSending an PF_PACKET allows to bypass the CAN framework logic and to\ndirectly reach the xmit() function of a CAN driver. The only check\nwhich is performed by the PF_PACKET framework is to make sure that\nskb->len fits the interface's MTU.\n\nUnfortunately, because the sun4i_can driver does not populate its\nnet_device_ops->ndo_change_mtu(), it is possible for an attacker to\nconfigure an invalid MTU by doing, for example:\n\n  $ ip link set can0 mtu 9999\n\nAfter doing so, the attacker could open a PF_PACKET socket using the\nETH_P_CANXL protocol:\n\n\tsocket(PF_PACKET, SOCK_RAW, htons(ETH_P_CANXL))\n\nto inject a malicious CAN XL frames. For example:\n\n\tstruct canxl_frame frame = {\n\t\t.flags = 0xff,\n\t\t.len = 2048,\n\t};\n\nThe CAN drivers' xmit() function are calling can_dev_dropped_skb() to\ncheck that the skb is valid, unfortunately under above conditions, the\nmalicious packet is able to go through can_dev_dropped_skb() checks:\n\n  1. the skb->protocol is set to ETH_P_CANXL which is valid (the\n     function does not check the actual device capabilities).\n\n  2. the length is a valid CAN XL length.\n\nAnd so, sun4ican_start_xmit() receives a CAN XL frame which it is not\nable to correctly handle and will thus misinterpret it as a CAN frame.\n\nThis can result in a buffer overflow. The driver will consume cf->len\nas-is with no further checks on this line:\n\n\tdlc = cf->len;\n\nHere, cf->len corresponds to the flags field of the CAN XL frame. In\nour previous example, we set canxl_frame->flags to 0xff. Because the\nmaximum expected length is 8, a buffer overflow of 247 bytes occurs a\ncouple line below when doing:\n\n\tfor (i = 0; i < dlc; i++)\n\t\twritel(cf->data[i], priv->base + (dreg + i * 4));\n\nPopulate net_device_ops->ndo_change_mtu() to ensure that the\ninterface's MTU can not be set to anything bigger than CAN_MTU. By\nfixing the root cause, this prevents the buffer overflow."}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/can/sun4i_can.c"],"versions":[{"version":"0738eff14d817a02ab082c392c96a1613006f158","lessThan":"063539db42203b29d5aa2adf0cae3d68c646a6b6","status":"affected","versionType":"git"},{"version":"0738eff14d817a02ab082c392c96a1613006f158","lessThan":"4f382cc887adca8478b9d3e6b81aa6698a95fff4","status":"affected","versionType":"git"},{"version":"0738eff14d817a02ab082c392c96a1613006f158","lessThan":"60463a1c138900494cb3adae41142a11cd8feb3c","status":"affected","versionType":"git"},{"version":"0738eff14d817a02ab082c392c96a1613006f158","lessThan":"a61ff7ac93270d20ca426c027d6d01c8ac8e904c","status":"affected","versionType":"git"},{"version":"0738eff14d817a02ab082c392c96a1613006f158","lessThan":"2e423e1990f3972cbea779883fef52c2f2acb858","status":"affected","versionType":"git"},{"version":"0738eff14d817a02ab082c392c96a1613006f158","lessThan":"de77841652e57afbc46e9e1dbf51ee364fc008e1","status":"affected","versionType":"git"},{"version":"0738eff14d817a02ab082c392c96a1613006f158","lessThan":"7f7b21026a6febdb749f6f6f950427245aa86cce","status":"affected","versionType":"git"},{"version":"0738eff14d817a02ab082c392c96a1613006f158","lessThan":"61da0bd4102c459823fbe6b8b43b01fb6ace4a22","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/can/sun4i_can.c"],"versions":[{"version":"4.4","status":"affected"},{"version":"0","lessThan":"4.4","status":"unaffected","versionType":"semver"},{"version":"5.4.300","lessThanOrEqual":"5.4.*","status":"unaffected","versionType":"semver"},{"version":"5.10.245","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.194","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.155","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.109","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.50","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.16.10","lessThanOrEqual":"6.16.*","status":"unaffected","versionType":"semver"},{"version":"6.17","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.4","versionEndExcluding":"5.4.300"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.4","versionEndExcluding":"5.10.245"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.4","versionEndExcluding":"5.15.194"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.4","versionEndExcluding":"6.1.155"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.4","versionEndExcluding":"6.6.109"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.4","versionEndExcluding":"6.12.50"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.4","versionEndExcluding":"6.16.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.4","versionEndExcluding":"6.17"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/063539db42203b29d5aa2adf0cae3d68c646a6b6"},{"url":"https://git.kernel.org/stable/c/4f382cc887adca8478b9d3e6b81aa6698a95fff4"},{"url":"https://git.kernel.org/stable/c/60463a1c138900494cb3adae41142a11cd8feb3c"},{"url":"https://git.kernel.org/stable/c/a61ff7ac93270d20ca426c027d6d01c8ac8e904c"},{"url":"https://git.kernel.org/stable/c/2e423e1990f3972cbea779883fef52c2f2acb858"},{"url":"https://git.kernel.org/stable/c/de77841652e57afbc46e9e1dbf51ee364fc008e1"},{"url":"https://git.kernel.org/stable/c/7f7b21026a6febdb749f6f6f950427245aa86cce"},{"url":"https://git.kernel.org/stable/c/61da0bd4102c459823fbe6b8b43b01fb6ace4a22"}],"title":"can: sun4i_can: populate ndo_change_mtu() to prevent buffer overflow","x_generator":{"engine":"bippy-1.2.0"}}}}