{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-23300", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-01-13T15:37:45.993Z", "datePublished": "2026-03-25T10:26:56.138Z", "dateUpdated": "2026-07-14T12:46:30.393Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-05-11T22:04:13.060Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ipv6: fix panic when IPv4 route references loopback IPv6 nexthop\n\nWhen a standalone IPv6 nexthop object is created with a loopback device\n(e.g., \"ip -6 nexthop add id 100 dev lo\"), fib6_nh_init() misclassifies\nit as a reject route. This is because nexthop objects have no destination\nprefix (fc_dst=::), causing fib6_is_reject() to match any loopback\nnexthop. The reject path skips fib_nh_common_init(), leaving\nnhc_pcpu_rth_output unallocated. If an IPv4 route later references this\nnexthop, __mkroute_output() dereferences NULL nhc_pcpu_rth_output and\npanics.\n\nSimplify the check in fib6_nh_init() to only match explicit reject\nroutes (RTF_REJECT) instead of using fib6_is_reject(). The loopback\npromotion heuristic in fib6_is_reject() is handled separately by\nip6_route_info_create_nh(). After this change, the three cases behave\nas follows:\n\n1. Explicit reject route (\"ip -6 route add unreachable 2001:db8::/64\"):\n RTF_REJECT is set, enters reject path, skips fib_nh_common_init().\n No behavior change.\n\n2. Implicit loopback reject route (\"ip -6 route add 2001:db8::/32 dev lo\"):\n RTF_REJECT is not set, takes normal path, fib_nh_common_init() is\n called. ip6_route_info_create_nh() still promotes it to reject\n afterward. nhc_pcpu_rth_output is allocated but unused, which is\n harmless.\n\n3. Standalone nexthop object (\"ip -6 nexthop add id 100 dev lo\"):\n RTF_REJECT is not set, takes normal path, fib_nh_common_init() is\n called. nhc_pcpu_rth_output is properly allocated, fixing the crash\n when IPv4 routes reference this nexthop." } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ipv6/route.c" ], "versions": [ { "version": "493ced1ac47c48bb86d9d4e8e87df8592be85a0e", "lessThan": "607e68c1b7c5a30c795571be1906d716e989a644", "status": "affected", "versionType": "git" }, { "version": "493ced1ac47c48bb86d9d4e8e87df8592be85a0e", "lessThan": "c11d7c56c2076ee9cd72004f1976fe0734df2ae9", "status": "affected", "versionType": "git" }, { "version": "493ced1ac47c48bb86d9d4e8e87df8592be85a0e", "lessThan": "b5062fc2150614c9ea8a611c2e0cb6e047ebfa3a", "status": "affected", "versionType": "git" }, { "version": "493ced1ac47c48bb86d9d4e8e87df8592be85a0e", "lessThan": "b299121e7453d23faddf464087dff513a495b4fc", "status": "affected", "versionType": "git" }, { "version": "493ced1ac47c48bb86d9d4e8e87df8592be85a0e", "lessThan": "f7c9f8e3607440fe39300efbaf46cf7b5eecb23f", "status": "affected", "versionType": "git" }, { "version": "493ced1ac47c48bb86d9d4e8e87df8592be85a0e", "lessThan": "b3b5a037d520afe3d5276e653bc0ff516bbda34c", "status": "affected", "versionType": "git" }, { "version": "493ced1ac47c48bb86d9d4e8e87df8592be85a0e", "lessThan": "8650db85b4259d2885d2a80fbc2317ce24194133", "status": "affected", "versionType": "git" }, { "version": "493ced1ac47c48bb86d9d4e8e87df8592be85a0e", "lessThan": "21ec92774d1536f71bdc90b0e3d052eff99cf093", "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/ipv6/route.c" ], "versions": [ { "version": "5.3", "status": "affected" }, { "version": "0", "lessThan": "5.3", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.253", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.203", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.167", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.130", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.77", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.17", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19.7", "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": "5.3", "versionEndExcluding": "5.10.253" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "5.15.203" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "6.1.167" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "6.6.130" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "6.12.77" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "6.18.17" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "6.19.7" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "7.0" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/607e68c1b7c5a30c795571be1906d716e989a644" }, { "url": "https://git.kernel.org/stable/c/c11d7c56c2076ee9cd72004f1976fe0734df2ae9" }, { "url": "https://git.kernel.org/stable/c/b5062fc2150614c9ea8a611c2e0cb6e047ebfa3a" }, { "url": "https://git.kernel.org/stable/c/b299121e7453d23faddf464087dff513a495b4fc" }, { "url": "https://git.kernel.org/stable/c/f7c9f8e3607440fe39300efbaf46cf7b5eecb23f" }, { "url": "https://git.kernel.org/stable/c/b3b5a037d520afe3d5276e653bc0ff516bbda34c" }, { "url": "https://git.kernel.org/stable/c/8650db85b4259d2885d2a80fbc2317ce24194133" }, { "url": "https://git.kernel.org/stable/c/21ec92774d1536f71bdc90b0e3d052eff99cf093" } ], "title": "net: ipv6: fix panic when IPv4 route references loopback IPv6 nexthop", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "x_adpType": "supplier", "providerMetadata": { "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-07-14T12:46:30.393Z" }, "affected": [ { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.6", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.5", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.6", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518-4 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