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Critical 9.8Published May 1, 2026

CVE-2026-43011net/x25: Fix potential double free of skb

Updated under an hour ago ()

Does this affect you?

It affects Linux and 4 other products. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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
9.8 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE)
Not given
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
Linux
NVD analysis
Modified
Record last updated
Oct 16, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
Linux Linux
linux:linux (from the name)
from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 5d0aa038a90b30c9bedde0c41c1fdcd98ecb16e9; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 3f5e3005984645bf5bd129c6b13149879580b1fb; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before f782dd382203b2a8c4552a628431b7de65a19a7b; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 143d4fa68ae9efb83b0c55b12cc7f0d03732a2b1; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 524371398d8463ea7e101fce2cbf3915645d1730; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before fa1dbc93530b34fab0da9862426fe9c918c74dc0; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before c87dd137c0dad07cc55f98181ff380b0c23d2878; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before d10a26aa4d072320530e6968ef945c8c575edf61
CNA record
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)
from V3.1.6
CISA ADP
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name)
from V3.1.6
CISA ADP
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)
from V3.1.6
CISA ADP
linux linux_kernel
linux:linux_kernel
from 2.6.12.1 before 5.10.253; from 5.11 before 5.15.203; from 5.16 before 6.1.168; from 6.2 before 6.6.134; from 6.7 before 6.12.81; from 6.13 before 6.18.22; from 6.19 before 6.19.12; 2.6.12; and 10 more ranges
NVD

References

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The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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