{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-99074", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.389Z", "datePublished": "2026-10-23T12:23:17.866Z", "dateUpdated": "2026-10-23T12:23:17.866Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-23T12:23:17.866Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv4: stop PMTU walk when nexthop group shrinks\n\nCommit 7d3f3b4367f3 (\"net: ipv4: Cache pmtu for all packet paths if\nmultipath enabled\") made __ip_rt_update_pmtu() update every path.\n\nFor nexthop objects, fib_info_num_path() and fib_info_nhc()\nindependently load nh->nh_grp. RCU protects each group's lifetime but\ndoes not make the loads observe the same group. If replacement shrinks\nthe group after the loop accepts an index, fib_info_nhc() returns NULL\nand update_or_create_fnhe() dereferences it.\n\nA deterministic probe only widened the existing window between the real\noperations. On v7.2, an RTM_NEWNEXTHOP replacement published a\none-member group after the PMTU reader accepted index 1 from a two-member\ngroup, producing:\n\n KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]\n RIP: update_or_create_fnhe+0x45/0x15b0\n\nStop when the indexed path is absent. Groups are dense, so no later\nindex exists in that snapshot. The same real-writer window completed\n114,423 PMTU iterations without an oops with this check. A reproducer\nis available on request.\n\nReplacement requires CAP_NET_ADMIN in the network namespace. Where\nunprivileged user namespaces are permitted, a local user can obtain it\nin a new user and 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/route.c" ], "versions": [ { "version": "3bed2abab4a682d426624ce9add9d7b6d475d4e4", "lessThan": "7fd60d3c9a1e1b11ef5f1643bbae78d91eae2f4a", "status": "affected", "versionType": "git" }, { "version": "7f5005457b3072fe1ddf15bfef869f2a1d98e05e", "lessThan": "c60d17d6dd61adc761ac6f65a008fefbc54cbf87", "status": "affected", "versionType": "git" }, { "version": "7d3f3b4367f315a61fc615e3138f3d320da8c466", "lessThan": "c6d670ac656badfd0e15355e07a13a6bdf3b69fd", "status": "affected", "versionType": "git" }, { "version": "7d3f3b4367f315a61fc615e3138f3d320da8c466", "lessThan": "f27483f9975b5065ff67054cc7eb8edac6083488", "status": "affected", "versionType": "git" }, { "version": "7d3f3b4367f315a61fc615e3138f3d320da8c466", "lessThan": "6619e01855e65ef35723685a557e3eb106f4ecf5", "status": "affected", "versionType": "git" }, { "version": "fc07a232326a623d0be482e307c08ea7049c2846", "status": "affected", "versionType": "git" }, { "version": "b1f7bdee5750d6cbb9497140cd6582abc5fdcb9e", "status": "affected", "versionType": "git" }, { "version": "6.6.79", "lessThan": "6.6.160", "status": "affected", "versionType": "semver" }, { "version": "6.12.16", "lessThan": "6.12.113", "status": "affected", "versionType": "semver" }, { "version": "5.15.179", "lessThan": "5.16", "status": "affected", "versionType": "semver" }, { "version": "6.1.129", "lessThan": "6.2", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ipv4/route.c" ], "versions": [ { "version": "6.13", "status": "affected" }, { "version": "0", "lessThan": "6.13", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.160", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.113", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.57", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.11", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "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": "6.6.79", "versionEndExcluding": "6.6.160" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12.16", "versionEndExcluding": "6.12.113" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "6.18.57" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "7.2.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "7.3" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15.179" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1.129" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/7fd60d3c9a1e1b11ef5f1643bbae78d91eae2f4a" }, { "url": "https://git.kernel.org/stable/c/c60d17d6dd61adc761ac6f65a008fefbc54cbf87" }, { "url": "https://git.kernel.org/stable/c/c6d670ac656badfd0e15355e07a13a6bdf3b69fd" }, { "url": "https://git.kernel.org/stable/c/f27483f9975b5065ff67054cc7eb8edac6083488" }, { "url": "https://git.kernel.org/stable/c/6619e01855e65ef35723685a557e3eb106f4ecf5" } ], "title": "ipv4: stop PMTU walk when nexthop group shrinks", "x_generator": { "engine": "bippy-1.2.0" } } } }