{"id":"CVE-2025-21891","state":"PUBLISHED","title":"ipvlan: ensure network headers are in skb linear part","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nipvlan: ensure network headers are in skb linear part\n\nsyzbot found that ipvlan_process_v6_outbound() was assuming\nthe IPv6 network header isis present in skb->head [1]\n\nAdd the needed pskb_network_may_pull() calls for both\nIPv4 and IPv6 handlers.\n\n[1]\nBUG: KMSAN: uninit-value in __ipv6_addr_type+0xa2/0x490 net/ipv6/addrconf_core.c:47\n  __ipv6_addr_type+0xa2/0x490 net/ipv6/addrconf_core.c:47\n  ipv6_addr_type include/net/ipv6.h:555 [inline]\n  ip6_route_output_flags_noref net/ipv6/route.c:2616 [inline]\n  ip6_route_output_flags+0x51/0x720 net/ipv6/route.c:2651\n  ip6_route_output include/net/ip6_route.h:93 [inline]\n  ipvlan_route_v6_outbound+0x24e/0x520 drivers/net/ipvlan/ipvlan_core.c:476\n  ipvlan_process_v6_outbound drivers/net/ipvlan/ipvlan_core.c:491 [inline]\n  ipvlan_process_outbound drivers/net/ipvlan/ipvlan_core.c:541 [inline]\n  ipvlan_xmit_mode_l3 drivers/net/ipvlan/ipvlan_core.c:605 [inline]\n  ipvlan_queue_xmit+0xd72/0x1780 drivers/net/ipvlan/ipvlan_core.c:671\n  ipvlan_start_xmit+0x5b/0x210 drivers/net/ipvlan/ipvlan_main.c:223\n  __netdev_start_xmit include/linux/netdevice.h:5150 [inline]\n  netdev_start_xmit include/linux/netdevice.h:5159 [inline]\n  xmit_one net/core/dev.c:3735 [inline]\n  dev_hard_start_xmit+0x247/0xa20 net/core/dev.c:3751\n  sch_direct_xmit+0x399/0xd40 net/sched/sch_generic.c:343\n  qdisc_restart net/sched/sch_generic.c:408 [inline]\n  __qdisc_run+0x14da/0x35d0 net/sched/sch_generic.c:416\n  qdisc_run+0x141/0x4d0 include/net/pkt_sched.h:127\n  net_tx_action+0x78b/0x940 net/core/dev.c:5484\n  handle_softirqs+0x1a0/0x7c0 kernel/softirq.c:561\n  __do_softirq+0x14/0x1a kernel/softirq.c:595\n  do_softirq+0x9a/0x100 kernel/softirq.c:462\n  __local_bh_enable_ip+0x9f/0xb0 kernel/softirq.c:389\n  local_bh_enable include/linux/bottom_half.h:33 [inline]\n  rcu_read_unlock_bh include/linux/rcupdate.h:919 [inline]\n  __dev_queue_xmit+0x2758/0x57d0 net/core/dev.c:4611\n  dev_queue_xmit include/linux/netdevice.h:3311 [inline]\n  packet_xmit+0x9c/0x6c0 net/packet/af_packet.c:276\n  packet_snd net/packet/af_packet.c:3132 [inline]\n  packet_sendmsg+0x93e0/0xa7e0 net/packet/af_packet.c:3164\n  sock_sendmsg_nosec net/socket.c:718 [inline]","publishedAt":"2025-03-27T14:57:17.267Z","updatedAt":"2026-05-11T21:08:31.288Z","severity":{"score":5.5,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","source":"CISA-ADP"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"2ad7bf3638411cb547f2823df08166c13ab04269","status":"affected","lessThan":"5b8dea8d1612dc7151d2457d7d2e6a69820309bf","versionType":"git"},{"version":"2ad7bf3638411cb547f2823df08166c13ab04269","status":"affected","lessThan":"4ec48f812804f370f622e0874e6dd8fcc58241cd","versionType":"git"},{"version":"2ad7bf3638411cb547f2823df08166c13ab04269","status":"affected","lessThan":"5353fd89663c48f56bdff975c562cfe78b1a2e4c","versionType":"git"},{"version":"2ad7bf3638411cb547f2823df08166c13ab04269","status":"affected","lessThan":"e2a4f76a2d8a44816ecd25bcbdb47b786d621974","versionType":"git"},{"version":"2ad7bf3638411cb547f2823df08166c13ab04269","status":"affected","lessThan":"27843ce6ba3d3122b65066550fe33fb8839f8aef","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/ipvlan/ipvlan_core.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.19","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.19","versionType":"semver"},{"version":"6.1.130","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.81","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.18","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.13.6","status":"unaffected","lessThanOrEqual":"6.13.*","versionType":"semver"},{"version":"6.14","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/ipvlan/ipvlan_core.c"]}],"references":["https://git.kernel.org/stable/c/5b8dea8d1612dc7151d2457d7d2e6a69820309bf","https://git.kernel.org/stable/c/4ec48f812804f370f622e0874e6dd8fcc58241cd","https://git.kernel.org/stable/c/5353fd89663c48f56bdff975c562cfe78b1a2e4c","https://git.kernel.org/stable/c/e2a4f76a2d8a44816ecd25bcbdb47b786d621974","https://git.kernel.org/stable/c/27843ce6ba3d3122b65066550fe33fb8839f8aef","https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html"],"weaknesses":["CWE-908"],"ingestedAt":"2026-10-29T20:08:39.238Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/21xxx/CVE-2025-21891.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-21891","state":"PUBLISHED","datePublished":"2025-03-27T14:57:17.267Z","dateUpdated":"2026-05-11T21:08:31.288Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2024-12-29T08:45:45.783Z"},"containers":{"cna":{"title":"ipvlan: ensure network headers are in skb linear part","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nipvlan: ensure network headers are in skb linear part\n\nsyzbot found that ipvlan_process_v6_outbound() was assuming\nthe IPv6 network header isis present in skb->head [1]\n\nAdd the needed pskb_network_may_pull() calls for both\nIPv4 and IPv6 handlers.\n\n[1]\nBUG: KMSAN: uninit-value in __ipv6_addr_type+0xa2/0x490 net/ipv6/addrconf_core.c:47\n  __ipv6_addr_type+0xa2/0x490 net/ipv6/addrconf_core.c:47\n  ipv6_addr_type include/net/ipv6.h:555 [inline]\n  ip6_route_output_flags_noref net/ipv6/route.c:2616 [inline]\n  ip6_route_output_flags+0x51/0x720 net/ipv6/route.c:2651\n  ip6_route_output include/net/ip6_route.h:93 [inline]\n  ipvlan_route_v6_outbound+0x24e/0x520 drivers/net/ipvlan/ipvlan_core.c:476\n  ipvlan_process_v6_outbound drivers/net/ipvlan/ipvlan_core.c:491 [inline]\n  ipvlan_process_outbound drivers/net/ipvlan/ipvlan_core.c:541 [inline]\n  ipvlan_xmit_mode_l3 drivers/net/ipvlan/ipvlan_core.c:605 [inline]\n  ipvlan_queue_xmit+0xd72/0x1780 drivers/net/ipvlan/ipvlan_core.c:671\n  ipvlan_start_xmit+0x5b/0x210 drivers/net/ipvlan/ipvlan_main.c:223\n  __netdev_start_xmit include/linux/netdevice.h:5150 [inline]\n  netdev_start_xmit include/linux/netdevice.h:5159 [inline]\n  xmit_one net/core/dev.c:3735 [inline]\n  dev_hard_start_xmit+0x247/0xa20 net/core/dev.c:3751\n  sch_direct_xmit+0x399/0xd40 net/sched/sch_generic.c:343\n  qdisc_restart net/sched/sch_generic.c:408 [inline]\n  __qdisc_run+0x14da/0x35d0 net/sched/sch_generic.c:416\n  qdisc_run+0x141/0x4d0 include/net/pkt_sched.h:127\n  net_tx_action+0x78b/0x940 net/core/dev.c:5484\n  handle_softirqs+0x1a0/0x7c0 kernel/softirq.c:561\n  __do_softirq+0x14/0x1a kernel/softirq.c:595\n  do_softirq+0x9a/0x100 kernel/softirq.c:462\n  __local_bh_enable_ip+0x9f/0xb0 kernel/softirq.c:389\n  local_bh_enable include/linux/bottom_half.h:33 [inline]\n  rcu_read_unlock_bh include/linux/rcupdate.h:919 [inline]\n  __dev_queue_xmit+0x2758/0x57d0 net/core/dev.c:4611\n  dev_queue_xmit include/linux/netdevice.h:3311 [inline]\n  packet_xmit+0x9c/0x6c0 net/packet/af_packet.c:276\n  packet_snd net/packet/af_packet.c:3132 [inline]\n  packet_sendmsg+0x93e0/0xa7e0 net/packet/af_packet.c:3164\n  sock_sendmsg_nosec net/socket.c:718 [inline]"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"2ad7bf3638411cb547f2823df08166c13ab04269","status":"affected","lessThan":"5b8dea8d1612dc7151d2457d7d2e6a69820309bf","versionType":"git"},{"version":"2ad7bf3638411cb547f2823df08166c13ab04269","status":"affected","lessThan":"4ec48f812804f370f622e0874e6dd8fcc58241cd","versionType":"git"},{"version":"2ad7bf3638411cb547f2823df08166c13ab04269","status":"affected","lessThan":"5353fd89663c48f56bdff975c562cfe78b1a2e4c","versionType":"git"},{"version":"2ad7bf3638411cb547f2823df08166c13ab04269","status":"affected","lessThan":"e2a4f76a2d8a44816ecd25bcbdb47b786d621974","versionType":"git"},{"version":"2ad7bf3638411cb547f2823df08166c13ab04269","status":"affected","lessThan":"27843ce6ba3d3122b65066550fe33fb8839f8aef","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/ipvlan/ipvlan_core.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.19","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.19","versionType":"semver"},{"version":"6.1.130","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.81","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.18","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.13.6","status":"unaffected","lessThanOrEqual":"6.13.*","versionType":"semver"},{"version":"6.14","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/ipvlan/ipvlan_core.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/5b8dea8d1612dc7151d2457d7d2e6a69820309bf"},{"url":"https://git.kernel.org/stable/c/4ec48f812804f370f622e0874e6dd8fcc58241cd"},{"url":"https://git.kernel.org/stable/c/5353fd89663c48f56bdff975c562cfe78b1a2e4c"},{"url":"https://git.kernel.org/stable/c/e2a4f76a2d8a44816ecd25bcbdb47b786d621974"},{"url":"https://git.kernel.org/stable/c/27843ce6ba3d3122b65066550fe33fb8839f8aef"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-05-11T21:08:31.288Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.19","versionEndExcluding":"6.1.130"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.19","versionEndExcluding":"6.6.81"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.19","versionEndExcluding":"6.12.18"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.19","versionEndExcluding":"6.13.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.19","versionEndExcluding":"6.14"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":5.5,"attackVector":"LOCAL","baseSeverity":"MEDIUM","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","integrityImpact":"NONE","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"HIGH","privilegesRequired":"LOW","confidentialityImpact":"NONE"}},{"other":{"type":"ssvc","content":{"id":"CVE-2025-21891","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2025-10-01T19:25:21.205802Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-908","lang":"en","type":"CWE","description":"CWE-908 Use of Uninitialized Resource"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2025-10-01T19:26:36.702Z"}},{"title":"CVE Program Container","references":[{"url":"https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html"}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2025-11-03T19:38:41.627Z"}}]}}}