CVE ID :CVE-2026-52943<\/p>\n
Published : June 24, 2026, 9 a.m. | 2\u00a0hours, 44\u00a0minutes ago<\/p>\n
Description :In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
net: skbuff: fix missing zerocopy reference in pskb_carve helpers<\/p>\n
pskb_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.<\/p>\n
KASAN reports use-after-free on a freed ubuf_info_msgzc:<\/p>\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<\/p>\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<\/p>\n
Allocated by task 219:
\n msg_zerocopy_realloc+0x157\/0x7b0
\n tcp_sendmsg_locked+0x2892\/0x3ba0<\/p>\n
Freed by task 219:
\n ip_recv_error+0x74a\/0xb10
\n tcp_recvmsg+0x475\/0x530<\/p>\n
The 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.<\/p>\n
The 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().<\/p>\n
Severity: 0.0 | NA<\/p>\n
Visit the link for more details, such as CVSS details, affected products, timeline, and more…\u00a0<\/p>\n","protected":false},"excerpt":{"rendered":"
CVE ID :CVE-2026-52943 Published : June 24, 2026, 9 a.m. | 2\u00a0hours, 44\u00a0minutes ago Description :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) …<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[26],"tags":[],"class_list":["post-81007","post","type-post","status-publish","format-standard","hentry","category-vulnerability"],"_links":{"self":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/posts\/81007","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/comments?post=81007"}],"version-history":[{"count":0,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/posts\/81007\/revisions"}],"wp:attachment":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/media?parent=81007"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/categories?post=81007"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/tags?post=81007"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}