{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-74577","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-08-15T05:44:03.917Z","datePublished":"2026-08-15T12:28:14.408Z","dateUpdated":"2026-08-19T16:39:14.107Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-19T16:39:14.107Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: mpls: initialize rtm_tos in mpls_getroute()\n\nmpls_getroute() builds the RTM_NEWROUTE reply to an RTM_GETROUTE\nrequest by filling a struct rtmsg allocated from an skb whose data\narea is not zeroed (alloc_skb(NLMSG_GOODSIZE, ...)). It sets every\nfield of the header except rtm_tos:\n\n\tr = nlmsg_data(nlh);\n\tr->rtm_family\t = AF_MPLS;\n\tr->rtm_dst_len\t= 20;\n\tr->rtm_src_len\t= 0;\n\tr->rtm_table\t= RT_TABLE_MAIN;\n\tr->rtm_type\t= RTN_UNICAST;\n\tr->rtm_scope\t= RT_SCOPE_UNIVERSE;\n\tr->rtm_protocol = rt->rt_protocol;\n\tr->rtm_flags\t= 0;\n\nstruct rtmsg has no padding, so the one uninitialised byte rtm_tos\n(offset 3) is copied straight to user space on recvmsg(), leaking a\nbyte of uninitialised heap memory. This is in contrast to\nmpls_dump_route(), which fills the very same header and does set\nrtm_tos = 0.\n\nInitialize rtm_tos to 0, matching mpls_dump_route().\n\nReproduced with KMSAN by adding an MPLS route and issuing a\nnon-RTM_F_FIB_MATCH RTM_GETROUTE for its label:\n\n  BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x36c/0x33f0\n   _copy_to_iter+0x36c/0x33f0\n   __skb_datagram_iter+0x196/0x12c0\n   skb_copy_datagram_iter+0x5b/0x210\n   netlink_recvmsg+0x37b/0xef0\n   ...\n  Uninit was created at:\n   __alloc_skb+0x8ca/0x10e0\n   mpls_getroute+0x1280/0x3a40\n   rtnetlink_rcv_msg+0x1138/0x15a0\n   ...\n  Byte 19 of 64 is uninitialized\n\n(byte 19 = nlmsghdr(16) + rtmsg offset 3 = rtm_tos)"}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/mpls/af_mpls.c"],"versions":[{"version":"397fc9e5cefee0c33b86811fbddb0decb7288c52","lessThan":"248718fd88b146d8bdc7610ecd1eb4cd16e0b5a1","status":"affected","versionType":"git"},{"version":"397fc9e5cefee0c33b86811fbddb0decb7288c52","lessThan":"466b474a8deb0c93b5280c6d261e5eda6482eca7","status":"affected","versionType":"git"},{"version":"397fc9e5cefee0c33b86811fbddb0decb7288c52","lessThan":"ba56f88aab18d982f2a21f11390f4d8a8897782a","status":"affected","versionType":"git"},{"version":"397fc9e5cefee0c33b86811fbddb0decb7288c52","lessThan":"95651461cf77cc6590fa08c87667717e5dcfa55d","status":"affected","versionType":"git"},{"version":"397fc9e5cefee0c33b86811fbddb0decb7288c52","lessThan":"1fea5ff0eb4aa7e951bb3d380248566c473aa377","status":"affected","versionType":"git"},{"version":"397fc9e5cefee0c33b86811fbddb0decb7288c52","lessThan":"a5cdd2407dd890f741f59b8367e4c6c101cce154","status":"affected","versionType":"git"},{"version":"397fc9e5cefee0c33b86811fbddb0decb7288c52","lessThan":"2dc2fffc704a4365cae1aae078ba62223aaeff93","status":"affected","versionType":"git"},{"version":"397fc9e5cefee0c33b86811fbddb0decb7288c52","lessThan":"295dd295e2137e10e9a5b1891d97e0f08de76f03","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/mpls/af_mpls.c"],"versions":[{"version":"4.13","status":"affected"},{"version":"0","lessThan":"4.13","status":"unaffected","versionType":"semver"},{"version":"5.10.265","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.216","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.183","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.151","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.103","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.44","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.1.8","lessThanOrEqual":"7.1.*","status":"unaffected","versionType":"semver"},{"version":"7.2","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":"4.13","versionEndExcluding":"5.10.265"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.13","versionEndExcluding":"5.15.216"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.13","versionEndExcluding":"6.1.183"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.13","versionEndExcluding":"6.6.151"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.13","versionEndExcluding":"6.12.103"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.13","versionEndExcluding":"6.18.44"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.13","versionEndExcluding":"7.1.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.13","versionEndExcluding":"7.2"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/248718fd88b146d8bdc7610ecd1eb4cd16e0b5a1"},{"url":"https://git.kernel.org/stable/c/466b474a8deb0c93b5280c6d261e5eda6482eca7"},{"url":"https://git.kernel.org/stable/c/ba56f88aab18d982f2a21f11390f4d8a8897782a"},{"url":"https://git.kernel.org/stable/c/95651461cf77cc6590fa08c87667717e5dcfa55d"},{"url":"https://git.kernel.org/stable/c/1fea5ff0eb4aa7e951bb3d380248566c473aa377"},{"url":"https://git.kernel.org/stable/c/a5cdd2407dd890f741f59b8367e4c6c101cce154"},{"url":"https://git.kernel.org/stable/c/2dc2fffc704a4365cae1aae078ba62223aaeff93"},{"url":"https://git.kernel.org/stable/c/295dd295e2137e10e9a5b1891d97e0f08de76f03"}],"title":"net: mpls: initialize rtm_tos in mpls_getroute()","x_generator":{"engine":"bippy-1.2.0"}}}}