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Actively exploitedCVSS 7.8 · HIGH

CVE-2026-53362Privilege escalation in Linux IPv6 networking subsystem

Linux Kernel contains an unspecified vulnerability that can allow for privilege escalation via IPv6 networking subsystem. This vulnerability can impact multiple products, including but not limited to Suse, Red Hat, and other products using Linux.

View on NVD

Analysis

Esta vulnerabilidad en el subsistema IPv6 del Kernel de Linux permite a un atacante local escalar privilegios hasta obtener control total del sistema. El fallo está siendo explotado activamente en el mundo real y afecta a la infraestructura de servidores y nodos de contenedores basados en la mayoría de las distribuciones Linux. Se recomienda actualizar el kernel de inmediato en hosts físicos y virtuales.

Relevant roles

LinuxciberseguridadBackendCloudKubernetesDocker

Severity

Score: 7.8(HIGH)
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
AV: LOCAL
AC: LOW
PR: LOW
UI: NONE
S: UNCHANGED
C: HIGH
I: HIGH
A: HIGH
Weakness (CWE): NVD-CWE-noinfoCWE-122

CISA KEV

Added to KEV: 2026-08-27
Federal patch deadline: 2026-08-30
Known ransomware use: Unknown
Required action

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

EPSS

Probability of exploitation (next 30 days): 0.0027 (0.3%)
Percentile: 18.0%
EPSS: 2026-08-27

Affects

linux:linux_kernel

Technical description

In the Linux kernel, the following vulnerability has been resolved: ipv6: account for fraggap on the paged allocation path In __ip6_append_data(), when the paged-allocation branch is taken (MSG_MORE / NETIF_F_SG / large fraglen), alloclen and pagedlen are computed as alloclen = fragheaderlen + transhdrlen; pagedlen = datalen - transhdrlen; datalen already includes fraggap (datalen = length + fraggap). When fraggap is non-zero, this is not the first skb and transhdrlen is zero. The fraggap bytes carried over from the previous skb are copied just past the fragment headers in the new skb's linear area. The linear area is therefore undersized by fraggap bytes while pagedlen is overstated by the same amount, and the copy writes past skb->end into the trailing skb_shared_info. An unprivileged user can trigger this via a UDPv6 socket using MSG_MORE together with MSG_SPLICE_PAGES. The bad accounting was introduced by commit 773ba4fe9104 ("ipv6: avoid partial copy for zc"). Before commit ce650a166335 ("udp6: Fix __ip6_append_data()'s handling of MSG_SPLICE_PAGES"), the negative copy value caused -EINVAL to be returned. That later commit allowed MSG_SPLICE_PAGES to proceed in this case, making the corruption triggerable. The non-paged branch sets alloclen to fraglen, which already accounts for fraggap because datalen does. Bring the paged branch in line by adding fraggap to alloclen and subtracting it from pagedlen. After this adjustment, copy no longer collapses to -fraggap on the paged path, so remove the stale comment describing that old arithmetic. Since a negative copy is no longer expected for a valid MSG_SPLICE_PAGES case, remove the MSG_SPLICE_PAGES exception from the negative copy check.

Published: 7/4/2026, 12:17:02 PM
Last modified: 8/27/2026, 5:18:46 PM

References

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