{"id":"CVE-2026-43139","title":"xfrm6: fix uninitialized saddr in xfrm6_get_saddr()","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm6: fix uninitialized saddr in xfrm6_get_saddr()\n\nxfrm6_get_saddr() does not check the return value of\nipv6_dev_get_saddr(). When ipv6_dev_get_saddr() fails to find …","severity":"high","cvss":8.6,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= a1e59abf824969554b90facd44a4ab16e265afa4 < 4f28141786e1fe884ce42a5197ba9beed540f0ea","Linux >= a1e59abf824969554b90facd44a4ab16e265afa4 < 6535867673bf301d52aa00593a4d1d18cc3922fa","Linux >= a1e59abf824969554b90facd44a4ab16e265afa4 < eb2ee15290af14c60b45cf2b73f5687d1d077d9b","Linux >= a1e59abf824969554b90facd44a4ab16e265afa4 < 719918fc88df6da023dfff370cd965151a5afd7f","Linux >= a1e59abf824969554b90facd44a4ab16e265afa4 < dc0abce055134cb83b0d981d31ceb20dda419787","Linux >= a1e59abf824969554b90facd44a4ab16e265afa4 < c7221e7bd8fc2ef38a0b27be580d9d202281306b","Linux >= a1e59abf824969554b90facd44a4ab16e265afa4 < 3dcd1664ac15eee6a690daec7c4ffc59190406f7","Linux >= a1e59abf824969554b90facd44a4ab16e265afa4 < 1799d8abeabc68ec05679292aaf6cba93b343c05","Linux 2.6.19"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-10-16T15:15:07.789549Z"},"published":"2026-05-06","updated":"2026-10-16","sourceUpdated":"2026-10-16T15:20:34.389Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-43139","references":[{"url":"https://git.kernel.org/stable/c/4f28141786e1fe884ce42a5197ba9beed540f0ea"},{"url":"https://git.kernel.org/stable/c/6535867673bf301d52aa00593a4d1d18cc3922fa"},{"url":"https://git.kernel.org/stable/c/eb2ee15290af14c60b45cf2b73f5687d1d077d9b"},{"url":"https://git.kernel.org/stable/c/719918fc88df6da023dfff370cd965151a5afd7f"},{"url":"https://git.kernel.org/stable/c/dc0abce055134cb83b0d981d31ceb20dda419787"},{"url":"https://git.kernel.org/stable/c/c7221e7bd8fc2ef38a0b27be580d9d202281306b"},{"url":"https://git.kernel.org/stable/c/3dcd1664ac15eee6a690daec7c4ffc59190406f7"},{"url":"https://git.kernel.org/stable/c/1799d8abeabc68ec05679292aaf6cba93b343c05"}],"tags":["cve.org"],"epss":0.00375,"epssPercentile":0.29876,"ingestedAt":"2026-10-16T17:24:46.684Z","slug":"CVE-2026-43139","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nxfrm6: fix uninitialized saddr in xfrm6_get_saddr()\n\nxfrm6_get_saddr() does not check the return value of\nipv6_dev_get_saddr(). When ipv6_dev_get_saddr() fails to find a suitable\nsource address (returns -EADDRNOTAVAIL), saddr->in6 is left\nuninitialized, but xfrm6_get_saddr() still returns 0 (success).\n\nThis causes the caller xfrm_tmpl_resolve_one() to use the uninitialized\naddress in xfrm_state_find(), triggering KMSAN warning:\n\n=====================================================\nBUG: KMSAN: uninit-value in xfrm_state_find+0x2424/0xa940\n xfrm_state_find+0x2424/0xa940\n xfrm_resolve_and_create_bundle+0x906/0x5a20\n xfrm_lookup_with_ifid+0xcc0/0x3770\n xfrm_lookup_route+0x63/0x2b0\n ip_route_output_flow+0x1ce/0x270\n udp_sendmsg+0x2ce1/0x3400\n inet_sendmsg+0x1ef/0x2a0\n __sock_sendmsg+0x278/0x3d0\n __sys_sendto+0x593/0x720\n __x64_sys_sendto+0x130/0x200\n x64_sys_call+0x332b/0x3e70\n do_syscall_64+0xd3/0xf80\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nLocal variable tmp.i.i created at:\n xfrm_resolve_and_create_bundle+0x3e3/0x5a20\n xfrm_lookup_with_ifid+0xcc0/0x3770\n=====================================================\n\nFix by checking the return value of ipv6_dev_get_saddr() and propagating\nthe error.\n\n## Affected\n\n- `Linux >= a1e59abf824969554b90facd44a4ab16e265afa4 < 4f28141786e1fe884ce42a5197ba9beed540f0ea`\n- `Linux >= a1e59abf824969554b90facd44a4ab16e265afa4 < 6535867673bf301d52aa00593a4d1d18cc3922fa`\n- `Linux >= a1e59abf824969554b90facd44a4ab16e265afa4 < eb2ee15290af14c60b45cf2b73f5687d1d077d9b`\n- `Linux >= a1e59abf824969554b90facd44a4ab16e265afa4 < 719918fc88df6da023dfff370cd965151a5afd7f`\n- `Linux >= a1e59abf824969554b90facd44a4ab16e265afa4 < dc0abce055134cb83b0d981d31ceb20dda419787`\n- `Linux >= a1e59abf824969554b90facd44a4ab16e265afa4 < c7221e7bd8fc2ef38a0b27be580d9d202281306b`\n- `Linux >= a1e59abf824969554b90facd44a4ab16e265afa4 < 3dcd1664ac15eee6a690daec7c4ffc59190406f7`\n- `Linux >= a1e59abf824969554b90facd44a4ab16e265afa4 < 1799d8abeabc68ec05679292aaf6cba93b343c05`\n- `Linux 2.6.19`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":47,"depthScoreParts":{"impact":47.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}