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Vulnerability record · CVE-2026-43011 · published 1 May 2026

CVE-2026-43011: Linux kernel double free vulnerability

Linux · Linux Kernel

In the Linux kernel, the following vulnerability has been resolved: net/x25: Fix potential double free of skb When alloc_skb fails in x25_queue_rx_frame it calls kfree_skb(skb) at line 48 and returns 1 (error). This error propagates back through the call chain: x25_queue_rx_frame returns 1 | v x25_state3_machine receives the return value 1 and takes the else branch at line 278, setting queued=0 and returning 0 | v x25_process_rx_frame returns queued=0 | v x25_backlog_rcv at line 452 sees queued=0 and calls kfree_skb(skb) again This would free the same skb twice. Looking at x25_backlog_rcv: net/x25/x25_in.c:x25_backlog_rcv() { ... queued = x25_process_rx_frame(sk, skb); ... if (!queued) kfree_skb(skb); }

9.8 CVSS 3.1 Critical EPSS 0.87% · top 42.9% CWE-415 · Double free
9.8CVSS 3.1 base score
0.87%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
10References
14 Jul 2026Last modified by NVD

Description

In the Linux kernel, the following vulnerability has been resolved: net/x25: Fix potential double free of skb When alloc_skb fails in x25_queue_rx_frame it calls kfree_skb(skb) at line 48 and returns 1 (error). This error propagates back through the call chain: x25_queue_rx_frame returns 1 | v x25_state3_machine receives the return value 1 and takes the else branch at line 278, setting queued=0 and returning 0 | v x25_process_rx_frame returns queued=0 | v x25_backlog_rcv at line 452 sees queued=0 and calls kfree_skb(skb) again This would free the same skb twice. Looking at x25_backlog_rcv: net/x25/x25_in.c:x25_backlog_rcv() { ... queued = x25_process_rx_frame(sk, skb); ... if (!queued) kfree_skb(skb); }

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://git.kernel.org/stable/c/143d4fa68ae9efb83b0c55b12cc7f0d03732a2b1 Patch
https://git.kernel.org/stable/c/3f5e3005984645bf5bd129c6b13149879580b1fb Patch
https://git.kernel.org/stable/c/524371398d8463ea7e101fce2cbf3915645d1730 Patch
https://git.kernel.org/stable/c/5d0aa038a90b30c9bedde0c41c1fdcd98ecb16e9 Patch
https://git.kernel.org/stable/c/c87dd137c0dad07cc55f98181ff380b0c23d2878 Patch
https://git.kernel.org/stable/c/d10a26aa4d072320530e6968ef945c8c575edf61 Patch
https://git.kernel.org/stable/c/f782dd382203b2a8c4552a628431b7de65a19a7b Patch
https://git.kernel.org/stable/c/fa1dbc93530b34fab0da9862426fe9c918c74dc0 Patch
https://cert-portal.siemens.com/productcert/html/ssa-019113.html
https://cert-portal.siemens.com/productcert/html/ssa-082556.html

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Source: NIST National Vulnerability Database (record CVE-2026-43011), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.