Use-after-free in Linux kernel - CVE-2026-52943
Published: June 25, 2026
Vulnerability identifier: #VU135433
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-52943
CWE-ID: CWE-416
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Linux Foundation
Affected software:
Linux kernel
Linux kernel
Detailed vulnerability description
The vulnerability allows a local user to escalate privileges.
The vulnerability exists due to a use-after-free in pskb_carve_inside_header() and pskb_carve_inside_nonlinear() when copying skb_shared_info for MSG_ZEROCOPY skbs. A local user can trigger repeated zerocopy skb operations to escalate privileges.
The issue is caused by copying the destructor_arg pointer into a new skb_shared_info without incrementing the associated zerocopy reference count, which can prematurely free ubuf_info_msgzc while transmit skbs still hold live references.
How to mitigate CVE-2026-52943
Install security update from vendor's repository.
Sources
- https://git.kernel.org/stable/c/2e0e74c59b2761a414d9f48d7bee1e45220b2427
- https://git.kernel.org/stable/c/474d6c771d798bca84f0a140b611e36743511e18
- https://git.kernel.org/stable/c/8dbed691e43a50903658130bde0fcb5abc425b37
- https://git.kernel.org/stable/c/96a4713ae041cc85e712bac682cd2e644004d6c6
- https://git.kernel.org/stable/c/98d0912e9f841e5529a5b89a972805f34cb1c69d
- https://git.kernel.org/stable/c/9b40bdc2a3298225dffab8158208a0d8c6300578
- https://git.kernel.org/stable/c/ceafb893b12f23331dcc5ff9587e643c3a40ee9f
- https://git.kernel.org/stable/c/fd470f0a97b8e9a125f520265d2f3b088ffb5b8a