{"id":"CVE-2026-98532","state":"PUBLISHED","title":"ipv6: do not let ipv6_find_hdr() return an offset past the packet end","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: do not let ipv6_find_hdr() return an offset past the packet end\n\nipv6_find_hdr() walks the extension header chain, skipping each header by\nthe length that header itself declares.  ipv6_optlen() returns up to 2048,\nand the skip is never checked against skb->len, so the offset stored in\n*offset can point past the end of the packet.\n\nopenvswitch installs that offset as the transport header, and\nupdate_ipv6_checksum() then reads and writes the transport checksum field\nout of bounds:\n\n  BUG: KASAN: slab-use-after-free in inet_proto_csum_replace16+0x445/0x470\n  Read of size 2 at addr ffff88810b754b06 by task ovs_ipv6_oob/629\n  CPU: 4 UID: 1000 PID: 629 Comm: ovs_ipv6_oob Tainted: G N 7.3.0-rc3+ #348\n  Call Trace:\n   inet_proto_csum_replace16+0x445/0x470\n   set_ipv6_addr+0x3dd/0x460\n   do_execute_actions+0x6a3d/0x7c40\n   ovs_execute_actions+0xfd/0x480\n   ovs_packet_cmd_execute+0xc38/0xf20\n   genl_rcv_msg+0x59e/0x870\n   netlink_rcv_skb+0x18b/0x450\n   genl_rcv+0x2d/0x40\n   netlink_unicast+0x6bc/0xa20\n\n  The buggy address belongs to the object at ffff88810b754980\n   which belongs to the cache skbuff_small_head of size 704\n  The buggy address is located 390 bytes inside of\n   freed 704-byte region [ffff88810b754980, ffff88810b754c40)\n\nOther callers use that offset too, so bound it here rather than in one\ncaller.\n\nReject a header whose declared length does not fit in the packet.\nipv6_find_hdr() already fails with -EBADMSG on a malformed chain, so this\nadds no new failure mode.","publishedAt":"2026-10-18T15:17:50.490Z","updatedAt":"2026-10-24T14:09:19.064Z","severity":{"score":8.1,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"f8f626754ebeca613cf1af2e6f890cfde0e74d5b","status":"affected","lessThan":"ca96b38730e31357ef4a9d76af1336958ac670d7","versionType":"git"},{"version":"f8f626754ebeca613cf1af2e6f890cfde0e74d5b","status":"affected","lessThan":"531255de8971c06d5d5986f85fdc2525d707ba71","versionType":"git"},{"version":"f8f626754ebeca613cf1af2e6f890cfde0e74d5b","status":"affected","lessThan":"543354c6efb27eae3372a3a9674aeaa2a86e2b2c","versionType":"git"},{"version":"f8f626754ebeca613cf1af2e6f890cfde0e74d5b","status":"affected","lessThan":"dc92cb972e86790b8078337ec41015b748b8f8e5","versionType":"git"},{"version":"f8f626754ebeca613cf1af2e6f890cfde0e74d5b","status":"affected","lessThan":"1c70275ca87e769e1a52abc644d61372d8c016cb","versionType":"git"},{"version":"f8f626754ebeca613cf1af2e6f890cfde0e74d5b","status":"affected","lessThan":"1d42828565889632068fbc2983c34d57c66af4e0","versionType":"git"},{"version":"f8f626754ebeca613cf1af2e6f890cfde0e74d5b","status":"affected","lessThan":"4254d5878c320c19961dd0b8e1d0aca4800d8b7d","versionType":"git"},{"version":"f8f626754ebeca613cf1af2e6f890cfde0e74d5b","status":"affected","lessThan":"ee319bd3a0e976af5087cbe59ebc50a66f31d202","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv6/exthdrs_core.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.8","versionType":"semver"},{"version":"5.10.271","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.222","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.189","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.158","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.112","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.55","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.9","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv6/exthdrs_core.c"]}],"references":["https://git.kernel.org/stable/c/ca96b38730e31357ef4a9d76af1336958ac670d7","https://git.kernel.org/stable/c/531255de8971c06d5d5986f85fdc2525d707ba71","https://git.kernel.org/stable/c/543354c6efb27eae3372a3a9674aeaa2a86e2b2c","https://git.kernel.org/stable/c/dc92cb972e86790b8078337ec41015b748b8f8e5","https://git.kernel.org/stable/c/1c70275ca87e769e1a52abc644d61372d8c016cb","https://git.kernel.org/stable/c/1d42828565889632068fbc2983c34d57c66af4e0","https://git.kernel.org/stable/c/4254d5878c320c19961dd0b8e1d0aca4800d8b7d","https://git.kernel.org/stable/c/ee319bd3a0e976af5087cbe59ebc50a66f31d202"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:43.249Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/98xxx/CVE-2026-98532.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98532","state":"PUBLISHED","datePublished":"2026-10-18T15:17:50.490Z","dateUpdated":"2026-10-24T14:09:19.064Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.355Z"},"containers":{"cna":{"title":"ipv6: do not let ipv6_find_hdr() return an offset past the packet end","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: do not let ipv6_find_hdr() return an offset past the packet end\n\nipv6_find_hdr() walks the extension header chain, skipping each header by\nthe length that header itself declares.  ipv6_optlen() returns up to 2048,\nand the skip is never checked against skb->len, so the offset stored in\n*offset can point past the end of the packet.\n\nopenvswitch installs that offset as the transport header, and\nupdate_ipv6_checksum() then reads and writes the transport checksum field\nout of bounds:\n\n  BUG: KASAN: slab-use-after-free in inet_proto_csum_replace16+0x445/0x470\n  Read of size 2 at addr ffff88810b754b06 by task ovs_ipv6_oob/629\n  CPU: 4 UID: 1000 PID: 629 Comm: ovs_ipv6_oob Tainted: G N 7.3.0-rc3+ #348\n  Call Trace:\n   inet_proto_csum_replace16+0x445/0x470\n   set_ipv6_addr+0x3dd/0x460\n   do_execute_actions+0x6a3d/0x7c40\n   ovs_execute_actions+0xfd/0x480\n   ovs_packet_cmd_execute+0xc38/0xf20\n   genl_rcv_msg+0x59e/0x870\n   netlink_rcv_skb+0x18b/0x450\n   genl_rcv+0x2d/0x40\n   netlink_unicast+0x6bc/0xa20\n\n  The buggy address belongs to the object at ffff88810b754980\n   which belongs to the cache skbuff_small_head of size 704\n  The buggy address is located 390 bytes inside of\n   freed 704-byte region [ffff88810b754980, ffff88810b754c40)\n\nOther callers use that offset too, so bound it here rather than in one\ncaller.\n\nReject a header whose declared length does not fit in the packet.\nipv6_find_hdr() already fails with -EBADMSG on a malformed chain, so this\nadds no new failure mode."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"f8f626754ebeca613cf1af2e6f890cfde0e74d5b","status":"affected","lessThan":"ca96b38730e31357ef4a9d76af1336958ac670d7","versionType":"git"},{"version":"f8f626754ebeca613cf1af2e6f890cfde0e74d5b","status":"affected","lessThan":"531255de8971c06d5d5986f85fdc2525d707ba71","versionType":"git"},{"version":"f8f626754ebeca613cf1af2e6f890cfde0e74d5b","status":"affected","lessThan":"543354c6efb27eae3372a3a9674aeaa2a86e2b2c","versionType":"git"},{"version":"f8f626754ebeca613cf1af2e6f890cfde0e74d5b","status":"affected","lessThan":"dc92cb972e86790b8078337ec41015b748b8f8e5","versionType":"git"},{"version":"f8f626754ebeca613cf1af2e6f890cfde0e74d5b","status":"affected","lessThan":"1c70275ca87e769e1a52abc644d61372d8c016cb","versionType":"git"},{"version":"f8f626754ebeca613cf1af2e6f890cfde0e74d5b","status":"affected","lessThan":"1d42828565889632068fbc2983c34d57c66af4e0","versionType":"git"},{"version":"f8f626754ebeca613cf1af2e6f890cfde0e74d5b","status":"affected","lessThan":"4254d5878c320c19961dd0b8e1d0aca4800d8b7d","versionType":"git"},{"version":"f8f626754ebeca613cf1af2e6f890cfde0e74d5b","status":"affected","lessThan":"ee319bd3a0e976af5087cbe59ebc50a66f31d202","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv6/exthdrs_core.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.8","versionType":"semver"},{"version":"5.10.271","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.222","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.189","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.158","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.112","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.55","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.9","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv6/exthdrs_core.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/ca96b38730e31357ef4a9d76af1336958ac670d7"},{"url":"https://git.kernel.org/stable/c/531255de8971c06d5d5986f85fdc2525d707ba71"},{"url":"https://git.kernel.org/stable/c/543354c6efb27eae3372a3a9674aeaa2a86e2b2c"},{"url":"https://git.kernel.org/stable/c/dc92cb972e86790b8078337ec41015b748b8f8e5"},{"url":"https://git.kernel.org/stable/c/1c70275ca87e769e1a52abc644d61372d8c016cb"},{"url":"https://git.kernel.org/stable/c/1d42828565889632068fbc2983c34d57c66af4e0"},{"url":"https://git.kernel.org/stable/c/4254d5878c320c19961dd0b8e1d0aca4800d8b7d"},{"url":"https://git.kernel.org/stable/c/ee319bd3a0e976af5087cbe59ebc50a66f31d202"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":8.1,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:N - A routed IPv6 datagram can carry a short Destination Options header whose hdrlen declares up to 2048 bytes; __netif_receive_skb_core() -> netdev_frame_hook() -> ovs_vport_receive() -> parse_ipv6hdr() reaches the patched ipv6_find_hdr(), which returns a transport offset beyond skb->len.\nAC:H - Corruption requires the packet to match a preinstalled OVS_ACTION_ATTR_SET_MASKED IPv6 address-rewrite action that changes an address; although the sender controls nexthdr and hdrlen, that capability-gated datapath state is outside a remote attacker's control.\nPR:N - netdev_frame_hook() and ovs_vport_receive() process matching received packets without authentication or capability checks; GENL_UNS_ADMIN_PERM protects installation of the OVS flow, not the remote sender triggering it.\nUI:N - Once the affected OVS rewrite flow exists, packet receipt automatically runs parse_ipv6hdr(), ovs_dp_process_packet(), and set_ipv6_addr() without any victim action.\nS:U - The bad offset from ipv6_find_hdr() and the resulting skbuff corruption occur within the same host kernel networking security authority; this is ordinary in-kernel compromise rather than a boundary-enforcement bypass.\nC:H - inet_proto_csum_replace16() reads the attacker-selected out-of-range 16-bit location before rewriting it; hdrlen can place this access in adjacent or reclaimed skbuff_small_head storage, where corrupting skb pointer or length metadata can enable broader kernel-memory disclosure.\nI:H - inet_proto_csum_replace16() stores through tcp_hdr(), udp_hdr(), or icmp6_hdr() at the unchecked transport offset; hdrlen selects a location up to roughly 2 KiB past the packet and the IPv6 address delta controls the 16-bit modification, yielding an exploitable heap-write primitive.\nA:H - The demonstrated set_ipv6_addr() path produced a KASAN slab-use-after-free in inet_proto_csum_replace16(); repeated matching packets can corrupt adjacent skb storage and cause a kernel oops or panic."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-24T14:09:19.064Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"5.10.271"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"5.15.222"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"6.1.189"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"6.6.158"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"6.12.112"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"6.18.55"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"7.2.9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}