{ "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" } } } }