{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-46266","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-05-13T15:03:33.108Z","datePublished":"2026-06-03T15:50:07.907Z","dateUpdated":"2026-08-05T12:30:53.523Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T12:30:53.523Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ninet: RAW sockets using IPPROTO_RAW MUST drop incoming ICMP\n\nYizhou Zhao reported that simply having one RAW socket on protocol\nIPPROTO_RAW (255) was dangerous.\n\n  socket(AF_INET, SOCK_RAW, 255);\n\nA malicious incoming ICMP packet can set the protocol field to 255\nand match this socket, leading to FNHE cache changes.\n\ninner = IP(src=\"192.168.2.1\", dst=\"8.8.8.8\", proto=255)/Raw(\"TEST\")\npkt = IP(src=\"192.168.1.1\", dst=\"192.168.2.1\")/ICMP(type=3, code=4, nexthopmtu=576)/inner\n\n\"man 7 raw\" states:\n\n  A protocol of IPPROTO_RAW implies enabled IP_HDRINCL and is able\n  to send any IP protocol that is specified in the passed header.\n  Receiving of all IP protocols via IPPROTO_RAW is not possible\n  using raw sockets.\n\nMake sure we drop these malicious packets."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H","baseScore":9.1,"baseSeverity":"CRITICAL"},"scenarios":[{"lang":"en","value":"AV:N - The bug is reached when a remotely sourced ICMP error (DEST_UNREACH/FRAG_NEEDED or REDIRECT) is received and processed through icmp_rcv() → icmp_unreach()/icmp_redirect() → icmp_socket_deliver(), which is standard internet-facing IPv4 input on any host accepting ICMP.\nAC:L - Exploitation is a single, deterministic crafted ICMP packet (inner IP proto=255, attacker-chosen daddr/PMTU) matching an open IPPROTO_RAW socket; an attacker can reliably create that socket via CAP_NET_RAW in a user+network namespace (unshare -Urn) without winning a race.\nPR:N - The network trigger requires no authentication or victim credentials—only delivery of forged ICMP to the target IP; the remote attacker does not need local privileges even though a local IPPROTO_RAW socket must exist on the victim (typically opened by a daemon or a co-resident userns holder).\nUI:N - No victim user action is required beyond normal network operation; the attacker sends ICMP directly to the host without tricking anyone into clicking, mounting, or opening files.\nS:U - Impact is confined to the kernel IPv4 routing/FNHE cache within the same network namespace; it does not cross a VM/hypervisor or IOMMU security boundary.\nC:N - This is a missing validation/logic bug that poisons route-cache metadata (PMTU/gateway); there is no memory read, pointer leak, or information-disclosure primitive.\nI:H - Before the fix, raw_err() unconditionally calls ipv4_sk_update_pmtu()/ipv4_sk_redirect(), letting a remote attacker inject attacker-controlled PMTU and gateway values into the system-wide FNHE exception cache for arbitrary destination addresses, altering forwarding for all local traffic to those destinations.\nA:H - Repeated forged ICMP FRAG_NEEDED packets can persistently force minimum PMTU entries in FNHE for chosen destinations, causing severe throughput collapse and connectivity failure for affected flows across the entire host or shared network namespace."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv4/icmp.c","net/ipv6/icmp.c"],"versions":[{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"db76b75ede3810e7cf9cfea5067d4f3e0993768b","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"19e42490c89bac9a388f28179e66bebbef350f99","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"531c1aec81bfe19d00af13da5531fbb8209e4bd2","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"719d3932b8f6e3348ce2f0ac58e278301fc17575","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"c89477ad79446867394360b29bb801010fc3ff22","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv4/icmp.c","net/ipv6/icmp.c"],"versions":[{"version":"2.6.12","status":"affected"},{"version":"0","lessThan":"2.6.12","status":"unaffected","versionType":"semver"},{"version":"6.6.128","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.75","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.14","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"6.19.4","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":"2.6.12","versionEndExcluding":"6.6.128"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.12.75"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.18.14"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.19.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"7.0"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/db76b75ede3810e7cf9cfea5067d4f3e0993768b"},{"url":"https://git.kernel.org/stable/c/19e42490c89bac9a388f28179e66bebbef350f99"},{"url":"https://git.kernel.org/stable/c/531c1aec81bfe19d00af13da5531fbb8209e4bd2"},{"url":"https://git.kernel.org/stable/c/719d3932b8f6e3348ce2f0ac58e278301fc17575"},{"url":"https://git.kernel.org/stable/c/c89477ad79446867394360b29bb801010fc3ff22"}],"title":"inet: RAW sockets using IPPROTO_RAW MUST drop incoming ICMP","x_generator":{"engine":"bippy-1.2.0"}}}}