CVE-2026-52943

In the Linux kernel, the following vulnerability has been resolved: net: skbuff: fix missing zerocopy reference in pskb_carve helpers pskb_carve_inside_header() and pskb_carve_inside_nonlinear() both copy the old skb_shared_info header into a new buffer via memcpy(), which includes the destructor_arg pointer (uarg) for MSG_ZEROCOPY skbs. Neither function calls net_zcopy_get() for the new shinfo, creating an unaccounted holder: every skb_shared_info with destructor_arg set will call skb_zcopy_clear() once when freed, but the corresponding net_zcopy_get() was never called for the new copy. Repeated calls drive uarg->refcnt to zero prematurely, freeing ubuf_info_msgzc while TX skbs still hold live destructor_arg pointers. KASAN reports use-after-free on a freed ubuf_info_msgzc: BUG: KASAN: slab-use-after-free in skb_release_data+0x77b/0x810 Read of size 8 at addr ffff88801574d3e8 by task poc/220 Call Trace: skb_release_data+0x77b/0x810 kfree_skb_list_reason+0x13e/0x610 skb_release_data+0x4cd/0x810 sk_skb_reason_drop+0xf3/0x340 skb_queue_purge_reason+0x282/0x440 rds_tcp_inc_free+0x1e/0x30 rds_recvmsg+0x354/0x1780 __sys_recvmsg+0xdf/0x180 Allocated by task 219: msg_zerocopy_realloc+0x157/0x7b0 tcp_sendmsg_locked+0x2892/0x3ba0 Freed by task 219: ip_recv_error+0x74a/0xb10 tcp_recvmsg+0x475/0x530 The skb consuming the late access still referenced the same uarg via shinfo->destructor_arg copied by pskb_carve_inside_nonlinear() without a refcount bump. This has been verified to be reliably exploitable: a working proof-of-concept achieves full root privilege escalation from an unprivileged local user on a default kernel configuration. The fix follows the pattern of pskb_expand_head() which has the same memcpy/cloned structure. For pskb_carve_inside_header(), net_zcopy_get() is placed after skb_orphan_frags() succeeds, so the orphan error path needs no cleanup. For pskb_carve_inside_nonlinear(), net_zcopy_get() is placed after all failure points and just before skb_release_data(), so no error path needs cleanup at all -- matching pskb_expand_head() more closely and avoiding the need for a balancing net_zcopy_put().
Configurations

Configuration 1 (hide)

OR cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:*

History

08 Jul 2026, 20:28

Type Values Removed Values Added
CWE CWE-416
References () https://git.kernel.org/stable/c/2e0e74c59b2761a414d9f48d7bee1e45220b2427 - () https://git.kernel.org/stable/c/2e0e74c59b2761a414d9f48d7bee1e45220b2427 - Patch
References () https://git.kernel.org/stable/c/474d6c771d798bca84f0a140b611e36743511e18 - () https://git.kernel.org/stable/c/474d6c771d798bca84f0a140b611e36743511e18 - Patch
References () https://git.kernel.org/stable/c/8dbed691e43a50903658130bde0fcb5abc425b37 - () https://git.kernel.org/stable/c/8dbed691e43a50903658130bde0fcb5abc425b37 - Patch
References () https://git.kernel.org/stable/c/96a4713ae041cc85e712bac682cd2e644004d6c6 - () https://git.kernel.org/stable/c/96a4713ae041cc85e712bac682cd2e644004d6c6 - Patch
References () https://git.kernel.org/stable/c/98d0912e9f841e5529a5b89a972805f34cb1c69d - () https://git.kernel.org/stable/c/98d0912e9f841e5529a5b89a972805f34cb1c69d - Patch
References () https://git.kernel.org/stable/c/9b40bdc2a3298225dffab8158208a0d8c6300578 - () https://git.kernel.org/stable/c/9b40bdc2a3298225dffab8158208a0d8c6300578 - Patch
References () https://git.kernel.org/stable/c/ceafb893b12f23331dcc5ff9587e643c3a40ee9f - () https://git.kernel.org/stable/c/ceafb893b12f23331dcc5ff9587e643c3a40ee9f - Patch
References () https://git.kernel.org/stable/c/fd470f0a97b8e9a125f520265d2f3b088ffb5b8a - () https://git.kernel.org/stable/c/fd470f0a97b8e9a125f520265d2f3b088ffb5b8a - Patch
References () https://access.redhat.com/security/cve/CVE-2026-52943 - () https://access.redhat.com/security/cve/CVE-2026-52943 - Third Party Advisory
References () https://bugzilla.redhat.com/show_bug.cgi?id=2492137 - () https://bugzilla.redhat.com/show_bug.cgi?id=2492137 - Third Party Advisory
References () https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52943.json - () https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52943.json - Third Party Advisory
First Time Linux linux Kernel
Linux
CPE cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:*

30 Jun 2026, 03:20

Type Values Removed Values Added
References
  • () https://access.redhat.com/security/cve/CVE-2026-52943 -
  • () https://bugzilla.redhat.com/show_bug.cgi?id=2492137 -
  • () https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52943.json -
CWE CWE-911

28 Jun 2026, 08:16

Type Values Removed Values Added
CVSS v2 : unknown
v3 : unknown
v2 : unknown
v3 : 7.8

24 Jun 2026, 10:17

Type Values Removed Values Added
New CVE

Information

Published : 2026-06-24 10:17

Updated : 2026-07-15 01:16


NVD link : CVE-2026-52943

Mitre link : CVE-2026-52943

CVE.ORG link : CVE-2026-52943


JSON object : View

Products Affected

linux

  • linux_kernel
CWE
CWE-416

Use After Free

CWE-911

Improper Update of Reference Count