{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-64027", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T07:54:57.028Z", "datePublished": "2026-07-19T15:39:18.470Z", "dateUpdated": "2026-08-05T12:38:22.063Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:38:22.063Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: shaper: rework the VALID marking (again)\n\nRecent commit changed the semantics from NOT_VALID to VALID.\nI didn't realize that the flags are not stored atomically\nwith the entry in XArray. There's still a race of reader\nobserving a VALID mark for a slot, getting interrupted,\nwriter replacing the entry with a different one, reader\ncontinuing, fetching the entry which is now a different\npointer than the pointer for which VALID was meant.\n\nThe biggest consequence of this is that we may see a UAF\nsince net_shaper_rollback() assumed that entries without\nVALID can be freed without observing RCU.\n\nLooks like the XArray marks are buying us nothing at this\npoint. Let's convert the code to an explicit valid field.\nThe smp_load_acquire() / smp_store_release() barriers are\nmarginally cleaner." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The vulnerability is reached only through the net-shaper generic netlink API (socket syscall), not via remote packet handling. This matches the kernel guidance for tc/netlink-style configuration subsystems.\nAC:L - The family sets parallel_ops, so an attacker can run concurrent SET/GROUP/DELETE and GET/dump requests to control both sides of the TOCTOU race. No attacker-uncontrollable memory layout or rare timing is required beyond issuing concurrent netlink operations.\nPR:L - Exploitation requires triggering net_shaper_rollback() via SET, GROUP, or DELETE, which are gated by GENL_ADMIN_PERM (CAP_NET_ADMIN). That capability is available to an unprivileged user inside a user network namespace, not only to init-namespace root.\nUI:N - Exploitation is fully programmatic through netlink messages and requires no victim interaction such as mounting a filesystem or opening a file.\nS:U - Impact is kernel heap corruption and privilege escalation within the same kernel; it does not cross a VM, container runtime, or IOMMU security boundary by itself.\nC:H - The commit explicitly identifies a use-after-free; concurrent RCU readers can dereference freed net_shaper objects, enabling arbitrary kernel memory disclosure via UAF exploitation.\nI:H - UAF on heap-allocated net_shaper structures can be leveraged for heap grooming and arbitrary write or control-flow hijack, consistent with standard kernel UAF impact.\nA:H - The UAF can cause kernel oops or panic on freed-object access during lookup, dump, or rollback, and matches kernel guidance that any UAF warrants 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/net_shaper.h", "net/shaper/shaper.c" ], "versions": [ { "version": "93954b40f6a4fc43226c01a15b02732f884500f1", "lessThan": "2417df5e7bb4184b9d3a2988036bf2c46e594545", "status": "affected", "versionType": "git" }, { "version": "93954b40f6a4fc43226c01a15b02732f884500f1", "lessThan": "96ea960dd40fd55302e0fd755176f26a95e6a50c", "status": "affected", "versionType": "git" }, { "version": "93954b40f6a4fc43226c01a15b02732f884500f1", "lessThan": "b8d7519352ba8c6df83259295d4a3bad093cae90", "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/net_shaper.h", "net/shaper/shaper.c" ], "versions": [ { "version": "6.13", "status": "affected" }, { "version": "0", "lessThan": "6.13", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.34", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0.11", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1", "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": "6.13", "versionEndExcluding": "6.18.34" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "7.0.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "7.1" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/2417df5e7bb4184b9d3a2988036bf2c46e594545" }, { "url": "https://git.kernel.org/stable/c/96ea960dd40fd55302e0fd755176f26a95e6a50c" }, { "url": "https://git.kernel.org/stable/c/b8d7519352ba8c6df83259295d4a3bad093cae90" } ], "title": "net: shaper: rework the VALID marking (again)", "x_generator": { "engine": "bippy-1.2.0" } } } }