{"attribution":"This product uses data from the NVD API but is not endorsed or certified by the NVD.","cve":{"id":"CVE-2026-98122","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","published":"2026-09-25T11:17:43.470","lastModified":"2026-10-22T17:19:22.093","vulnStatus":"Analyzed","cveTags":[],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nvxlan: mdb: Fix use-after-free in vxlan_mdb_remote_src_del()\n\nvxlan_mdb_is_valid_source(), which validates MDBE_ATTR_SOURCE and every\nMDBE_ATTR_SRC_LIST member, accepts the all-zeros address.\n\nA source list is only accepted on a (*, G) entry, whose source is the\nall-zeros address, and for each member of the list an (S, G) entry is\nderived from it by substituting the source. Entries are keyed by a plain\nmemcmp() of struct vxlan_mdb_entry_key, so if MDBE_ATTR_SOURCE is present\nand holds the all-zeros address and the source list holds it as well, the\nderived (S, G) key is byte-identical to the (*, G) key and resolves to the\nsame entry. Omitting MDBE_ATTR_SOURCE is not equivalent, as the key is\nthen left with a zero address family.\n\nvxlan_mdb_remote_src_del() removes the forwarding entry of a source before\nfreeing the source entry:\n\n\tvxlan_mdb_remote_src_fwd_del(vxlan, group, remote, \u0026ent-\u003eaddr);\n\tvxlan_mdb_remote_src_entry_del(ent);\n\nWith the keys aliased, the first call deletes the remote of the entry that\nowns 'ent' instead of a separate (S, G) entry, and frees 'ent'. The second\ncall then runs on the freed entry, and its hlist_del() reads -\u003epprev and\n-\u003enext out of it and writes through them.\n\nAdding the (*, G) entry with NLM_F_REPLACE and no source list marks the\nall-zeros source for deletion and reaches this from the sweep at the end\nof vxlan_mdb_remote_srcs_replace().\n\n  BUG: KASAN: slab-use-after-free in __vxlan_mdb_add+0x1cd/0xd70\n  Read of size 8 at addr ffff888102852500 by task poc/84\n   __vxlan_mdb_add+0x1cd/0xd70\n   vxlan_mdb_add+0xc0/0x140\n   rtnl_mdb_add+0x157/0x2a0\n   rtnetlink_rcv_msg+0x207/0x5a0\n  Allocated by task 84:\n   __kmalloc_cache_noprof+0x153/0x360\n   vxlan_mdb_remote_srcs_add+0x2eb/0x440\n   __vxlan_mdb_add+0x803/0xd70\n  Freed by task 84:\n   kfree+0x14c/0x3b0\n   vxlan_mdb_remote_del+0x129/0x1a0\n   __vxlan_mdb_del+0x4f/0xe0\n   vxlan_mdb_remote_src_fwd_del.isra.0+0x162/0x1b0\n   __vxlan_mdb_add+0x1c5/0xd70\n\nThe MDB operations are netns-scoped, so an unprivileged user can perform\nthem in a new user and network namespace.\n\nReject the all-zeros address in vxlan_mdb_is_valid_source(), which covers\nboth call sites. A (*, G) entry is expressed by omitting the source, so\nnothing legitimate is refused.\n\nDiscovered by XBOW, triaged by Baul Lee \u003cbaul.lee@xbow.com\u003e"}],"affected":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","affectedData":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","programFiles":["drivers/net/vxlan/vxlan_mdb.c","tools/testing/selftests/net/test_vxlan_mdb.sh"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","versions":[{"version":"a3a48de5eade770e911d35291217bdd69ce04ef1","lessThan":"069d5527bb0f229e528fa88c6b72f15060c373f2","versionType":"git","status":"affected"},{"version":"a3a48de5eade770e911d35291217bdd69ce04ef1","lessThan":"e12c903fd13c6261b98ca18d8f70ac26e739e2f8","versionType":"git","status":"affected"},{"version":"a3a48de5eade770e911d35291217bdd69ce04ef1","lessThan":"74e2a56c82209b0335b53e25f19f9b0590e2483d","versionType":"git","status":"affected"},{"version":"a3a48de5eade770e911d35291217bdd69ce04ef1","lessThan":"71203a41d6fa2fa0ea2f3a7541987958bd3694fd","versionType":"git","status":"affected"},{"version":"a3a48de5eade770e911d35291217bdd69ce04ef1","lessThan":"4aa61c88b4e292e10abdfd791334b8272108d68a","versionType":"git","status":"affected"}]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","programFiles":["drivers/net/vxlan/vxlan_mdb.c","tools/testing/selftests/net/test_vxlan_mdb.sh"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","versions":[{"version":"6.4","status":"affected"},{"version":"0","lessThan":"6.4","versionType":"semver","status":"unaffected"},{"version":"6.6.158","lessThanOrEqual":"6.6.*","versionType":"semver","status":"unaffected"},{"version":"6.12.111","lessThanOrEqual":"6.12.*","versionType":"semver","status":"unaffected"},{"version":"6.18.53","lessThanOrEqual":"6.18.*","versionType":"semver","status":"unaffected"},{"version":"7.2.7","lessThanOrEqual":"7.2.*","versionType":"semver","status":"unaffected"},{"version":"7.3","lessThanOrEqual":"*","versionType":"original_commit_for_fix","status":"unaffected"}]}]}],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":5.9}]},"weaknesses":[{"source":"nvd@nist.gov","type":"Primary","description":[{"lang":"en","value":"CWE-416"}]}],"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.4","versionEndExcluding":"6.6.158","matchCriteriaId":"0E70134D-9B4B-43A0-B5C8-9DCEDD74AB69"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"6.12.111","matchCriteriaId":"47BC31C9-3D9E-4B96-B5F8-291D6AD55D81"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.13","versionEndExcluding":"6.18.53","matchCriteriaId":"7561AABB-6D5A-4324-BC66-C6C6B012AFD8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.19","versionEndExcluding":"7.2.7","matchCriteriaId":"19917B2D-B4B2-4416-A482-9C7C4929A921"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:7.3:rc1:*:*:*:*:*:*","matchCriteriaId":"11E35E1B-5DB4-4AB9-9706-CD73B799EADF"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/069d5527bb0f229e528fa88c6b72f15060c373f2","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/4aa61c88b4e292e10abdfd791334b8272108d68a","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/71203a41d6fa2fa0ea2f3a7541987958bd3694fd","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/74e2a56c82209b0335b53e25f19f9b0590e2483d","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/e12c903fd13c6261b98ca18d8f70ac26e739e2f8","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]}]}}