{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-52943", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-06-09T07:44:35.371Z", "datePublished": "2026-06-24T09:00:12.292Z", "dateUpdated": "2026-08-05T12:31:55.528Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:31:55.528Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: skbuff: fix missing zerocopy reference in pskb_carve helpers\n\npskb_carve_inside_header() and pskb_carve_inside_nonlinear() both copy\nthe old skb_shared_info header into a new buffer via memcpy(), which\nincludes the destructor_arg pointer (uarg) for MSG_ZEROCOPY skbs.\nNeither function calls net_zcopy_get() for the new shinfo, creating an\nunaccounted holder: every skb_shared_info with destructor_arg set will\ncall skb_zcopy_clear() once when freed, but the corresponding\nnet_zcopy_get() was never called for the new copy. Repeated calls\ndrive uarg->refcnt to zero prematurely, freeing ubuf_info_msgzc while\nTX skbs still hold live destructor_arg pointers.\n\nKASAN reports use-after-free on a freed ubuf_info_msgzc:\n\n BUG: KASAN: slab-use-after-free in skb_release_data+0x77b/0x810\n Read of size 8 at addr ffff88801574d3e8 by task poc/220\n\n Call Trace:\n skb_release_data+0x77b/0x810\n kfree_skb_list_reason+0x13e/0x610\n skb_release_data+0x4cd/0x810\n sk_skb_reason_drop+0xf3/0x340\n skb_queue_purge_reason+0x282/0x440\n rds_tcp_inc_free+0x1e/0x30\n rds_recvmsg+0x354/0x1780\n __sys_recvmsg+0xdf/0x180\n\n Allocated by task 219:\n msg_zerocopy_realloc+0x157/0x7b0\n tcp_sendmsg_locked+0x2892/0x3ba0\n\n Freed by task 219:\n ip_recv_error+0x74a/0xb10\n tcp_recvmsg+0x475/0x530\n\nThe skb consuming the late access still referenced the same uarg via\nshinfo->destructor_arg copied by pskb_carve_inside_nonlinear() without\na refcount bump. This has been verified to be reliably exploitable: a\nworking proof-of-concept achieves full root privilege escalation from\nan unprivileged local user on a default kernel configuration.\n\nThe fix follows the pattern of pskb_expand_head() which has the same\nmemcpy/cloned structure. For pskb_carve_inside_header(), net_zcopy_get()\nis placed after skb_orphan_frags() succeeds, so the orphan error path\nneeds no cleanup. For pskb_carve_inside_nonlinear(), net_zcopy_get() is\nplaced after all failure points and just before skb_release_data(), so\nno error path needs cleanup at all -- matching pskb_expand_head() more\nclosely and avoiding the need for a balancing net_zcopy_put()." } ], "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 vulnerable zerocopy state is created by a local process using TCP MSG_ZEROCOPY; remote RDS/TCP packets can reach pskb_extract() but do not carry local ubuf_info destructor_arg state. A local unprivileged attacker can connect to the in-kernel RDS/TCP listener and send crafted zerocopy TCP data.\nAC:L - The fix commit states the issue is reliably exploitable with a working proof-of-concept, and the trigger is a deterministic missing reference count rather than an attacker-uncontrolled race. The attacker controls the local TCP connection, message layout, zerocopy sends, and repeated triggering.\nPR:L - The attack requires the ability to run local unprivileged code and create ordinary TCP sockets with SO_ZEROCOPY/MSG_ZEROCOPY, which has no capability check. No real root or init-namespace administrative privilege is required.\nUI:N - No victim user action is required once the local attacker runs the exploit. The attacker directly drives the socket operations and RDS/TCP receive path.\nS:U - The vulnerability is exploited within the kernel and impacts the same kernel security authority. It is a standard local kernel privilege escalation, not a VM escape or cross-scope boundary violation.\nC:H - This is a use-after-free of ubuf_info_msgzc reachable through skb zerocopy cleanup, and the fix commit confirms a working full root privilege-escalation exploit. Such kernel UAF exploitation can provide access to protected kernel and process memory.\nI:H - The stale ubuf_info pointer is later dereferenced through zerocopy completion handling, giving a memory-corruption primitive suitable for control-flow or credential manipulation. The reported exploit achieves full root privilege escalation.\nA:H - The bug produces a KASAN-confirmed slab use-after-free in skb_release_data() and can crash the kernel during skb cleanup. Even without full exploitation, repeated triggering can cause kernel oops/panic-level denial of service." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/core/skbuff.c" ], "versions": [ { "version": "6fa01ccd883021105e9f8af7d04b9f156fa3494a", "lessThan": "8dbed691e43a50903658130bde0fcb5abc425b37", "status": "affected", "versionType": "git" }, { "version": "6fa01ccd883021105e9f8af7d04b9f156fa3494a", "lessThan": "9b40bdc2a3298225dffab8158208a0d8c6300578", "status": "affected", "versionType": "git" }, { "version": "6fa01ccd883021105e9f8af7d04b9f156fa3494a", "lessThan": "fd470f0a97b8e9a125f520265d2f3b088ffb5b8a", "status": "affected", "versionType": "git" }, { "version": "6fa01ccd883021105e9f8af7d04b9f156fa3494a", "lessThan": "ceafb893b12f23331dcc5ff9587e643c3a40ee9f", "status": "affected", "versionType": "git" }, { "version": "6fa01ccd883021105e9f8af7d04b9f156fa3494a", "lessThan": "2e0e74c59b2761a414d9f48d7bee1e45220b2427", "status": "affected", "versionType": "git" }, { "version": "6fa01ccd883021105e9f8af7d04b9f156fa3494a", "lessThan": "96a4713ae041cc85e712bac682cd2e644004d6c6", "status": "affected", "versionType": "git" }, { "version": "6fa01ccd883021105e9f8af7d04b9f156fa3494a", "lessThan": "474d6c771d798bca84f0a140b611e36743511e18", "status": "affected", "versionType": "git" }, { "version": "6fa01ccd883021105e9f8af7d04b9f156fa3494a", "lessThan": "98d0912e9f841e5529a5b89a972805f34cb1c69d", "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/core/skbuff.c" ], "versions": [ { "version": "4.7", "status": "affected" }, { "version": "0", "lessThan": "4.7", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.259", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.210", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.176", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.143", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.93", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.35", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0.12", "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": "4.7", "versionEndExcluding": "5.10.259" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "5.15.210" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "6.1.176" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "6.6.143" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "6.12.93" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "6.18.35" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "7.0.12" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "7.1" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/8dbed691e43a50903658130bde0fcb5abc425b37" }, { "url": "https://git.kernel.org/stable/c/9b40bdc2a3298225dffab8158208a0d8c6300578" }, { "url": "https://git.kernel.org/stable/c/fd470f0a97b8e9a125f520265d2f3b088ffb5b8a" }, { "url": "https://git.kernel.org/stable/c/ceafb893b12f23331dcc5ff9587e643c3a40ee9f" }, { "url": "https://git.kernel.org/stable/c/2e0e74c59b2761a414d9f48d7bee1e45220b2427" }, { "url": "https://git.kernel.org/stable/c/96a4713ae041cc85e712bac682cd2e644004d6c6" }, { "url": "https://git.kernel.org/stable/c/474d6c771d798bca84f0a140b611e36743511e18" }, { "url": "https://git.kernel.org/stable/c/98d0912e9f841e5529a5b89a972805f34cb1c69d" } ], "title": "net: skbuff: fix missing zerocopy reference in pskb_carve helpers", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "affected": [ { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/o:redhat:enterprise_linux:10" ], "defaultStatus": "unaffected", "packageName": "kernel", "product": "Red Hat Enterprise Linux 10", "vendor": "Red Hat" }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/o:redhat:enterprise_linux:6" ], "defaultStatus": "unaffected", "packageName": "kernel", "product": "Red Hat Enterprise Linux 6", "vendor": "Red Hat" }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/o:redhat:enterprise_linux:7" ], "defaultStatus": "unaffected", "packageName": "kernel", "product": "Red Hat Enterprise Linux 7", "vendor": "Red Hat" }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/o:redhat:enterprise_linux:7" ], "defaultStatus": "unaffected", "packageName": "kernel-rt", "product": "Red Hat Enterprise Linux 7", "vendor": "Red Hat" }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/o:redhat:enterprise_linux:8" ], "defaultStatus": "unaffected", "packageName": "kernel", "product": "Red Hat Enterprise Linux 8", "vendor": "Red Hat" }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/o:redhat:enterprise_linux:8" ], "defaultStatus": "unaffected", "packageName": "kernel-rt", "product": "Red Hat Enterprise Linux 8", "vendor": "Red Hat" }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/o:redhat:enterprise_linux:9" ], "defaultStatus": "unaffected", "packageName": "kernel", "product": "Red Hat Enterprise Linux 9", "vendor": "Red Hat" }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/o:redhat:enterprise_linux:9" ], "defaultStatus": "unaffected", "packageName": "kernel-rt", "product": "Red Hat Enterprise Linux 9", "vendor": "Red Hat" } ], "datePublic": "2026-06-24T00:00:00.000Z", "descriptions": [ { "lang": "en", "value": "A flaw was found in the Linux kernel. The `pskb_carve_inside_header()` and `pskb_carve_inside_nonlinear()` helper functions, which handle network packet buffers, do not correctly account for zero-copy references. This oversight can lead to a use-after-free vulnerability, where memory is prematurely released while still in use. A local unprivileged user can exploit this flaw to achieve full root privilege escalation on the system." } ], "metrics": [ { "other": { "content": { "namespace": "https://access.redhat.com/security/updates/classification/", "value": "Important" }, "type": "Red Hat severity rating" } }, { "cvssV3_1": { "attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1" }, "format": "CVSS" } ], "problemTypes": [ { "descriptions": [ { "cweId": "CWE-911", "description": "Improper Update of Reference Count", "lang": "en", "type": "CWE" } ] } ], "references": [ { "tags": [ "vdb-entry", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/security/cve/CVE-2026-52943" }, { "name": "RHBZ#2492137", "tags": [ "issue-tracking", "x_refsource_REDHAT" ], "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2492137" }, { "tags": [ "x_sadp-csaf-vex" ], "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52943.json" } ], "timeline": [ { "lang": "en", "time": "2026-06-24T00:00:00.000Z", "value": "Reported to Red Hat." }, { "lang": "en", "time": "2026-06-24T00:00:00.000Z", "value": "Made public." } ], "title": "kernel: net: skbuff: fix missing zerocopy reference in pskb_carve helpers", "x_adpType": "supplier", "x_generator": { "engine": "sadp-cli 1.0.0" }, "providerMetadata": { "orgId": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "shortName": "redhat-SADP", "dateUpdated": "2026-07-15T00:45:57.638Z" } } ] } }