{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-23276", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-01-13T15:37:45.991Z", "datePublished": "2026-03-20T08:08:56.575Z", "dateUpdated": "2026-05-23T16:04:28.110Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-05-23T16:04:28.110Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: add xmit recursion limit to tunnel xmit functions\n\nTunnel xmit functions (iptunnel_xmit, ip6tunnel_xmit) lack their own\nrecursion limit. When a bond device in broadcast mode has GRE tap\ninterfaces as slaves, and those GRE tunnels route back through the\nbond, multicast/broadcast traffic triggers infinite recursion between\nbond_xmit_broadcast() and ip_tunnel_xmit()/ip6_tnl_xmit(), causing\nkernel stack overflow.\n\nThe existing XMIT_RECURSION_LIMIT (8) in the no-qdisc path is not\nsufficient because tunnel recursion involves route lookups and full IP\noutput, consuming much more stack per level. Use a lower limit of 4\n(IP_TUNNEL_RECURSION_LIMIT) to prevent overflow.\n\nAdd recursion detection using dev_xmit_recursion helpers directly in\niptunnel_xmit() and ip6tunnel_xmit() to cover all IPv4/IPv6 tunnel\npaths including UDP encapsulated tunnels (VXLAN, Geneve, etc.).\n\nMove dev_xmit_recursion helpers from net/core/dev.h to public header\ninclude/linux/netdevice.h so they can be used by tunnel code.\n\n BUG: KASAN: stack-out-of-bounds in blake2s.constprop.0+0xe7/0x160\n Write of size 32 at addr ffff88810033fed0 by task kworker/0:1/11\n Workqueue: mld mld_ifc_work\n Call Trace:\n \n __build_flow_key.constprop.0 (net/ipv4/route.c:515)\n ip_rt_update_pmtu (net/ipv4/route.c:1073)\n iptunnel_xmit (net/ipv4/ip_tunnel_core.c:84)\n ip_tunnel_xmit (net/ipv4/ip_tunnel.c:847)\n gre_tap_xmit (net/ipv4/ip_gre.c:779)\n dev_hard_start_xmit (net/core/dev.c:3887)\n sch_direct_xmit (net/sched/sch_generic.c:347)\n __dev_queue_xmit (net/core/dev.c:4802)\n bond_dev_queue_xmit (drivers/net/bonding/bond_main.c:312)\n bond_xmit_broadcast (drivers/net/bonding/bond_main.c:5279)\n bond_start_xmit (drivers/net/bonding/bond_main.c:5530)\n dev_hard_start_xmit (net/core/dev.c:3887)\n __dev_queue_xmit (net/core/dev.c:4841)\n ip_finish_output2 (net/ipv4/ip_output.c:237)\n ip_output (net/ipv4/ip_output.c:438)\n iptunnel_xmit (net/ipv4/ip_tunnel_core.c:86)\n gre_tap_xmit (net/ipv4/ip_gre.c:779)\n dev_hard_start_xmit (net/core/dev.c:3887)\n sch_direct_xmit (net/sched/sch_generic.c:347)\n __dev_queue_xmit (net/core/dev.c:4802)\n bond_dev_queue_xmit (drivers/net/bonding/bond_main.c:312)\n bond_xmit_broadcast (drivers/net/bonding/bond_main.c:5279)\n bond_start_xmit (drivers/net/bonding/bond_main.c:5530)\n dev_hard_start_xmit (net/core/dev.c:3887)\n __dev_queue_xmit (net/core/dev.c:4841)\n ip_finish_output2 (net/ipv4/ip_output.c:237)\n ip_output (net/ipv4/ip_output.c:438)\n iptunnel_xmit (net/ipv4/ip_tunnel_core.c:86)\n ip_tunnel_xmit (net/ipv4/ip_tunnel.c:847)\n gre_tap_xmit (net/ipv4/ip_gre.c:779)\n dev_hard_start_xmit (net/core/dev.c:3887)\n sch_direct_xmit (net/sched/sch_generic.c:347)\n __dev_queue_xmit (net/core/dev.c:4802)\n bond_dev_queue_xmit (drivers/net/bonding/bond_main.c:312)\n bond_xmit_broadcast (drivers/net/bonding/bond_main.c:5279)\n bond_start_xmit (drivers/net/bonding/bond_main.c:5530)\n dev_hard_start_xmit (net/core/dev.c:3887)\n __dev_queue_xmit (net/core/dev.c:4841)\n mld_sendpack\n mld_ifc_work\n process_one_work\n worker_thread\n " } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/linux/netdevice.h", "include/net/ip6_tunnel.h", "include/net/ip_tunnels.h", "net/core/dev.h", "net/ipv4/ip_tunnel_core.c" ], "versions": [ { "version": "745e20f1b626b1be4b100af5d4bf7b3439392f8f", "lessThan": "834c4f645726a25fd71ea50cdfb5c135f8f95d85", "status": "affected", "versionType": "git" }, { "version": "745e20f1b626b1be4b100af5d4bf7b3439392f8f", "lessThan": "8a57deeb256069f262957d8012418559ff66c385", "status": "affected", "versionType": "git" }, { "version": "745e20f1b626b1be4b100af5d4bf7b3439392f8f", "lessThan": "b56b8d19bd05e2a8338385c770bc2b60590bc81e", "status": "affected", "versionType": "git" }, { "version": "745e20f1b626b1be4b100af5d4bf7b3439392f8f", "lessThan": "6f1a9140ecda3baba3d945b9a6155af4268aafc4", "status": "affected", "versionType": "git" }, { "version": "3f266b04185de51d8e6446eb1fccec3b5e7ce575", "status": "affected", "versionType": "git" }, { "version": "2.6.35.9", "lessThan": "2.6.36", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/linux/netdevice.h", "include/net/ip6_tunnel.h", "include/net/ip_tunnels.h", "net/core/dev.h", "net/ipv4/ip_tunnel_core.c" ], "versions": [ { "version": "2.6.37", "status": "affected" }, { "version": "0", "lessThan": "2.6.37", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.78", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.19", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19.9", "lessThanOrEqual": "6.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.37", "versionEndExcluding": "6.12.78" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.37", "versionEndExcluding": "6.18.19" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.37", "versionEndExcluding": "6.19.9" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.37", "versionEndExcluding": "7.0" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.35.9" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/834c4f645726a25fd71ea50cdfb5c135f8f95d85" }, { "url": "https://git.kernel.org/stable/c/8a57deeb256069f262957d8012418559ff66c385" }, { "url": "https://git.kernel.org/stable/c/b56b8d19bd05e2a8338385c770bc2b60590bc81e" }, { "url": "https://git.kernel.org/stable/c/6f1a9140ecda3baba3d945b9a6155af4268aafc4" } ], "title": "net: add xmit recursion limit to tunnel xmit functions", "x_generator": { "engine": "bippy-1.2.0" } } } }