{"id":"CVE-2026-99088","state":"PUBLISHED","title":"net: openvswitch: validate transport header presence in set_ipv6_addr","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: openvswitch: validate transport header presence in set_ipv6_addr\n\nWhen executing IPv6 address rewrite actions on IPv6 fragments,\nset_ipv6_addr() calls update_ipv6_checksum(). If parse_ipv6hdr()\nprocesses a non-first IPv6 fragment, it sets key->ip.proto to\nNEXTHDR_FRAGMENT and returns early without calling\nskb_set_transport_header().\n\nupdate_ipv6_checksum() unconditionally evaluates skb_transport_offset()\non entry before checking l4_proto.  Because skb->transport_header is\nuninitialized, this triggers a warning under CONFIG_DEBUG_NET=y although\nit is completely harmless.\n\nFix this by returning early in update_ipv6_checksum() if l4_proto is\nNEXTHDR_FRAGMENT. This avoids reading the uninitialized transport offset\nfor fragments while preserving the debug warning for any other protocol\nwhere the transport header is unexpectedly missing.\n\nSee the syzbot trace:\n\n!skb_transport_header_was_set(skb)\nWARNING: ./include/linux/skbuff.h:3075 at skb_transport_header include/linux/skbuff.h:3075 [inline], CPU#1: syz-executor463/5635\nWARNING: ./include/linux/skbuff.h:3075 at skb_transport_offset include/linux/skbuff.h:3250 [inline], CPU#1: syz-executor463/5635\nWARNING: ./include/linux/skbuff.h:3075 at update_ipv6_checksum net/openvswitch/actions.c:361 [inline], CPU#1: syz-executor463/5635\nWARNING: ./include/linux/skbuff.h:3075 at set_ipv6_addr+0x462/0x660 net/openvswitch/actions.c:399, CPU#1: syz-executor463/5635\n[...]\nRIP: 0010:skb_transport_header include/linux/skbuff.h:3075 [inline]\nRIP: 0010:skb_transport_offset include/linux/skbuff.h:3250 [inline]\nRIP: 0010:update_ipv6_checksum net/openvswitch/actions.c:361 [inline]\nRIP: 0010:set_ipv6_addr+0x462/0x660 net/openvswitch/actions.c:399\n[...]\nCall Trace:\n <TASK>\n set_ipv6 net/openvswitch/actions.c:531 [inline]\n do_execute_actions+0x557e/0x8600 net/openvswitch/actions.c:1366\n ovs_execute_actions+0xde/0x520 net/openvswitch/actions.c:1592\n ovs_packet_cmd_execute+0xb4f/0xf10 net/openvswitch/datapath.c:705\n genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114\n genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209\n netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2572\n genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218\n netlink_unicast+0x7bd/0x940 net/netlink/af_netlink.c:1361\n netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1916\n sock_sendmsg_nosec+0x14e/0x190 net/socket.c:800","publishedAt":"2026-10-26T14:51:58.460Z","updatedAt":"2026-10-30T12:41:39.655Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"3fdbd1ce11e5c0d7cafbe44c942c5cad61113d7b","status":"affected","lessThan":"1efa6842e94aa70237446b31fbe2bc16586809c3","versionType":"git"},{"version":"3fdbd1ce11e5c0d7cafbe44c942c5cad61113d7b","status":"affected","lessThan":"ad4258db21e801a7aae614afca89a2e39283080d","versionType":"git"},{"version":"3fdbd1ce11e5c0d7cafbe44c942c5cad61113d7b","status":"affected","lessThan":"54cb98ed23866205926298621e04169f50665b59","versionType":"git"},{"version":"3fdbd1ce11e5c0d7cafbe44c942c5cad61113d7b","status":"affected","lessThan":"b7b80d204abdc258006f9e17c92b363ab13bb599","versionType":"git"},{"version":"3fdbd1ce11e5c0d7cafbe44c942c5cad61113d7b","status":"affected","lessThan":"6774af7cd17be8f0d0f70de3a749d381b4f2e9da","versionType":"git"},{"version":"3fdbd1ce11e5c0d7cafbe44c942c5cad61113d7b","status":"affected","lessThan":"2594795fd832f0253826d64ff8976b8ff5fbfe9f","versionType":"git"},{"version":"3fdbd1ce11e5c0d7cafbe44c942c5cad61113d7b","status":"affected","lessThan":"6b8897ba0733f88f0360ea48a970f373f9142de0","versionType":"git"},{"version":"3fdbd1ce11e5c0d7cafbe44c942c5cad61113d7b","status":"affected","lessThan":"3c6a4b11330fe424557538a98fca9f0a4c5bf313","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/openvswitch/actions.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.8","versionType":"semver"},{"version":"5.10.273","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.224","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.113","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.11","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/openvswitch/actions.c"]}],"references":["https://git.kernel.org/stable/c/1efa6842e94aa70237446b31fbe2bc16586809c3","https://git.kernel.org/stable/c/ad4258db21e801a7aae614afca89a2e39283080d","https://git.kernel.org/stable/c/54cb98ed23866205926298621e04169f50665b59","https://git.kernel.org/stable/c/b7b80d204abdc258006f9e17c92b363ab13bb599","https://git.kernel.org/stable/c/6774af7cd17be8f0d0f70de3a749d381b4f2e9da","https://git.kernel.org/stable/c/2594795fd832f0253826d64ff8976b8ff5fbfe9f","https://git.kernel.org/stable/c/6b8897ba0733f88f0360ea48a970f373f9142de0","https://git.kernel.org/stable/c/3c6a4b11330fe424557538a98fca9f0a4c5bf313"],"weaknesses":[],"ingestedAt":"2026-10-30T13:02:04.640Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/99xxx/CVE-2026-99088.json","commit":"cb14bf1b43b0c9f05f7f40eae2246263fd430780","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-99088","state":"PUBLISHED","datePublished":"2026-10-26T14:51:58.460Z","dateUpdated":"2026-10-30T12:41:39.655Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.390Z"},"containers":{"cna":{"title":"net: openvswitch: validate transport header presence in set_ipv6_addr","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: openvswitch: validate transport header presence in set_ipv6_addr\n\nWhen executing IPv6 address rewrite actions on IPv6 fragments,\nset_ipv6_addr() calls update_ipv6_checksum(). If parse_ipv6hdr()\nprocesses a non-first IPv6 fragment, it sets key->ip.proto to\nNEXTHDR_FRAGMENT and returns early without calling\nskb_set_transport_header().\n\nupdate_ipv6_checksum() unconditionally evaluates skb_transport_offset()\non entry before checking l4_proto.  Because skb->transport_header is\nuninitialized, this triggers a warning under CONFIG_DEBUG_NET=y although\nit is completely harmless.\n\nFix this by returning early in update_ipv6_checksum() if l4_proto is\nNEXTHDR_FRAGMENT. This avoids reading the uninitialized transport offset\nfor fragments while preserving the debug warning for any other protocol\nwhere the transport header is unexpectedly missing.\n\nSee the syzbot trace:\n\n!skb_transport_header_was_set(skb)\nWARNING: ./include/linux/skbuff.h:3075 at skb_transport_header include/linux/skbuff.h:3075 [inline], CPU#1: syz-executor463/5635\nWARNING: ./include/linux/skbuff.h:3075 at skb_transport_offset include/linux/skbuff.h:3250 [inline], CPU#1: syz-executor463/5635\nWARNING: ./include/linux/skbuff.h:3075 at update_ipv6_checksum net/openvswitch/actions.c:361 [inline], CPU#1: syz-executor463/5635\nWARNING: ./include/linux/skbuff.h:3075 at set_ipv6_addr+0x462/0x660 net/openvswitch/actions.c:399, CPU#1: syz-executor463/5635\n[...]\nRIP: 0010:skb_transport_header include/linux/skbuff.h:3075 [inline]\nRIP: 0010:skb_transport_offset include/linux/skbuff.h:3250 [inline]\nRIP: 0010:update_ipv6_checksum net/openvswitch/actions.c:361 [inline]\nRIP: 0010:set_ipv6_addr+0x462/0x660 net/openvswitch/actions.c:399\n[...]\nCall Trace:\n <TASK>\n set_ipv6 net/openvswitch/actions.c:531 [inline]\n do_execute_actions+0x557e/0x8600 net/openvswitch/actions.c:1366\n ovs_execute_actions+0xde/0x520 net/openvswitch/actions.c:1592\n ovs_packet_cmd_execute+0xb4f/0xf10 net/openvswitch/datapath.c:705\n genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114\n genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209\n netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2572\n genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218\n netlink_unicast+0x7bd/0x940 net/netlink/af_netlink.c:1361\n netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1916\n sock_sendmsg_nosec+0x14e/0x190 net/socket.c:800"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"3fdbd1ce11e5c0d7cafbe44c942c5cad61113d7b","status":"affected","lessThan":"1efa6842e94aa70237446b31fbe2bc16586809c3","versionType":"git"},{"version":"3fdbd1ce11e5c0d7cafbe44c942c5cad61113d7b","status":"affected","lessThan":"ad4258db21e801a7aae614afca89a2e39283080d","versionType":"git"},{"version":"3fdbd1ce11e5c0d7cafbe44c942c5cad61113d7b","status":"affected","lessThan":"54cb98ed23866205926298621e04169f50665b59","versionType":"git"},{"version":"3fdbd1ce11e5c0d7cafbe44c942c5cad61113d7b","status":"affected","lessThan":"b7b80d204abdc258006f9e17c92b363ab13bb599","versionType":"git"},{"version":"3fdbd1ce11e5c0d7cafbe44c942c5cad61113d7b","status":"affected","lessThan":"6774af7cd17be8f0d0f70de3a749d381b4f2e9da","versionType":"git"},{"version":"3fdbd1ce11e5c0d7cafbe44c942c5cad61113d7b","status":"affected","lessThan":"2594795fd832f0253826d64ff8976b8ff5fbfe9f","versionType":"git"},{"version":"3fdbd1ce11e5c0d7cafbe44c942c5cad61113d7b","status":"affected","lessThan":"6b8897ba0733f88f0360ea48a970f373f9142de0","versionType":"git"},{"version":"3fdbd1ce11e5c0d7cafbe44c942c5cad61113d7b","status":"affected","lessThan":"3c6a4b11330fe424557538a98fca9f0a4c5bf313","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/openvswitch/actions.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.8","versionType":"semver"},{"version":"5.10.273","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.224","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.113","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.11","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/openvswitch/actions.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/1efa6842e94aa70237446b31fbe2bc16586809c3"},{"url":"https://git.kernel.org/stable/c/ad4258db21e801a7aae614afca89a2e39283080d"},{"url":"https://git.kernel.org/stable/c/54cb98ed23866205926298621e04169f50665b59"},{"url":"https://git.kernel.org/stable/c/b7b80d204abdc258006f9e17c92b363ab13bb599"},{"url":"https://git.kernel.org/stable/c/6774af7cd17be8f0d0f70de3a749d381b4f2e9da"},{"url":"https://git.kernel.org/stable/c/2594795fd832f0253826d64ff8976b8ff5fbfe9f"},{"url":"https://git.kernel.org/stable/c/6b8897ba0733f88f0360ea48a970f373f9142de0"},{"url":"https://git.kernel.org/stable/c/3c6a4b11330fe424557538a98fca9f0a4c5bf313"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:41:39.655Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"5.10.273"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"5.15.224"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"6.12.113"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"6.18.57"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"7.2.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}