How severe is CVE-2026-43011?

CVE-2026-43011 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-43011 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-43011?

CVE-2026-43011 primarily affects Linux Linux Kernel. In total, 12 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-43011?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-43011 have an EU (EUVD) identifier?

Yes. CVE-2026-43011 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-26610.

When was CVE-2026-43011 published?

CVE-2026-43011 was published on 2026-05-01 and last updated on 2026-07-14.

CVE-2026-43011

CVE-2026-43011 is a critical-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-415.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 1% (46th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-26610
Weakness: CWE-415
Affected product: Linux Linux Kernel
Published: 2026-05-01
Last modified: 2026-07-14

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); }

Frequently asked questions

What is CVE-2026-43011?: 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); }
How severe is CVE-2026-43011?: CVE-2026-43011 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-43011 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-43011?: CVE-2026-43011 primarily affects Linux Linux Kernel. In total, 12 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-43011?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-43011 have an EU (EUVD) identifier?: Yes. CVE-2026-43011 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-26610.
When was CVE-2026-43011 published?: CVE-2026-43011 was published on 2026-05-01 and last updated on 2026-07-14.

References

Affected products (12)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.12:-:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.12:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.12:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.12:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.12:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*

More vulnerabilities in Linux Linux Kernel

CVE-2026-63795 — Critical (CVSS 10.0): In the Linux kernel, the following vulnerability has been resolved: 9p: avoid putting oldfid in p9_client_walk() error…
CVE-2025-38429 — Critical (CVSS 10.0): In the Linux kernel, the following vulnerability has been resolved: bus: mhi: ep: Update read pointer only after…
CVE-2025-22021 — Critical (CVSS 10.0): In the Linux kernel, the following vulnerability has been resolved: netfilter: socket: Lookup orig tuple for IPv6…
CVE-2025-21663 — Critical (CVSS 10.0): In the Linux kernel, the following vulnerability has been resolved: net: stmmac: dwmac-tegra: Read iommu stream id…
CVE-2024-56719 — Critical (CVSS 10.0): In the Linux kernel, the following vulnerability has been resolved: net: stmmac: fix TSO DMA API usage causing…
CVE-2024-44984 — Critical (CVSS 10.0): In the Linux kernel, the following vulnerability has been resolved: bnxt_en: Fix double DMA unmapping for…

All CVEs affecting Linux Linux Kernel →

Other CWE-415 (Double Free) vulnerabilities

CVE-2018-0101 — Critical (CVSS 10.0): A vulnerability in the Secure Sockets Layer (SSL) VPN functionality of the Cisco Adaptive Security Appliance (ASA)…
CVE-2026-8925 — Critical (CVSS 9.8): The curl logic that works with SASL authentication could end up cleaning up the GSASL context *twice* without clearing…
CVE-2026-52993 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: tipc: fix double-free in…
CVE-2020-37239 — Critical (CVSS 9.8): libbabl 0.1.62 contains a broken double free detection vulnerability that allows attackers to bypass memory safety…
CVE-2026-43414 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: scsi: qla2xxx: Completely fix fcport double…
CVE-2026-31609 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: smb: client: avoid double-free in…

Browse all CWE-415 (Double Free) vulnerabilities →