{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2026-98122", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-98122", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-09-25T10:36:05.369Z", "updatedAt": "2026-10-19T09:14:14.316Z", "importedAt": "2026-10-24T01:58:41.756Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "vxlan: mdb: Fix use-after-free in vxlan_mdb_remote_src_del()", "summary": "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, &ent->addr);\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 ->pprev and\n->next 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 ", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "a3a48de5eade770e911d35291217bdd69ce04ef1", "status": "affected", "versionType": "git", "lessThan": "069d5527bb0f229e528fa88c6b72f15060c373f2" }, { "version": "a3a48de5eade770e911d35291217bdd69ce04ef1", "status": "affected", "versionType": "git", "lessThan": "e12c903fd13c6261b98ca18d8f70ac26e739e2f8" }, { "version": "a3a48de5eade770e911d35291217bdd69ce04ef1", "status": "affected", "versionType": "git", "lessThan": "74e2a56c82209b0335b53e25f19f9b0590e2483d" }, { "version": "a3a48de5eade770e911d35291217bdd69ce04ef1", "status": "affected", "versionType": "git", "lessThan": "71203a41d6fa2fa0ea2f3a7541987958bd3694fd" }, { "version": "a3a48de5eade770e911d35291217bdd69ce04ef1", "status": "affected", "versionType": "git", "lessThan": "4aa61c88b4e292e10abdfd791334b8272108d68a" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "6.4", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "6.4" }, { "version": "6.6.158", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.111", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.18.53", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "7.2.7", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "7.2.*" }, { "version": "7.3", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }