{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-43042", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-05-01T14:12:55.978Z", "datePublished": "2026-05-01T14:15:38.882Z", "dateUpdated": "2026-08-05T12:25:30.622Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:25:30.622Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmpls: add seqcount to protect the platform_label{,s} pair\n\nThe RCU-protected codepaths (mpls_forward, mpls_dump_routes) can have\nan inconsistent view of platform_labels vs platform_label in case of a\nconcurrent resize (resize_platform_label_table, under\nplatform_mutex). This can lead to OOB accesses.\n\nThis patch adds a seqcount, so that we get a consistent snapshot.\n\nNote that mpls_label_ok is also susceptible to this, so the check\nagainst RTA_DST in rtm_to_route_config, done outside platform_mutex,\nis not sufficient. This value gets passed to mpls_label_ok once more\nin both mpls_route_add and mpls_route_del, so there is no issue, but\nthat additional check must not be removed." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H", "baseScore": 7.1, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The self-contained exploit path is local: the attacker races writes to /proc/sys/net/mpls/platform_labels with rtnetlink RTM_GETROUTE dumps in the same network namespace. Remote MPLS packets can reach one reader path, but a remote-only attacker cannot perform the required table resize.\nAC:L - The vulnerable condition is a race, but a local attacker can control both sides by repeatedly resizing platform_labels and issuing concurrent route dumps or packet processing. No external timing or victim state is required beyond retrying the race.\nPR:L - Writing the MPLS platform_labels sysctl requires CAP_NET_ADMIN over the target network namespace. That capability is reachable by an unprivileged user through a user namespace plus network namespace, so this is low privilege rather than high privilege.\nUI:N - No victim user action is required. The attacker can trigger the resize and reader paths directly.\nS:U - The bug is within the kernel networking/MPLS subsystem and impacts the same kernel security authority. It is not a VM escape or cross-authority boundary bypass.\nC:H - The inconsistent platform_labels/platform_label snapshot can cause out-of-bounds reads of the route pointer table and dereference attacker-influenced or adjacent kernel memory as mpls_route data. Through the route dump path this can disclose kernel memory, so confidentiality is high.\nI:N - The bug is an out-of-bounds read/dereference of the route table pointer array, not an out-of-bounds write or direct memory corruption primitive. The investigated paths do not provide a defensible arbitrary kernel data modification primitive.\nA:H - The race can make readers index a NULL, stale, or too-small platform_label array and dereference invalid pointers. This can reliably lead to kernel oops/panic or other high availability impact." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/net/netns/mpls.h", "net/mpls/af_mpls.c" ], "versions": [ { "version": "7720c01f3f590116882e251f13c7e1d5602f8643", "lessThan": "5bb3caf0bbfb56f1a00d2af072ac3d8395a3b9ef", "status": "affected", "versionType": "git" }, { "version": "7720c01f3f590116882e251f13c7e1d5602f8643", "lessThan": "629ec78ef8608d955ce217880cdc3e1873af3a15", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/net/netns/mpls.h", "net/mpls/af_mpls.c" ], "versions": [ { "version": "4.1", "status": "affected" }, { "version": "0", "lessThan": "4.1", "status": "unaffected", "versionType": "semver" }, { "version": "6.19.12", "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": "4.1", "versionEndExcluding": "6.19.12" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.1", "versionEndExcluding": "7.0" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/5bb3caf0bbfb56f1a00d2af072ac3d8395a3b9ef" }, { "url": "https://git.kernel.org/stable/c/629ec78ef8608d955ce217880cdc3e1873af3a15" } ], "title": "mpls: add seqcount to protect the platform_label{,s} pair", "x_generator": { "engine": "bippy-1.2.0" } } } }