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[ CVE-2026-53362 · Published 4 Jul 2026 ]

Linux Kernel Unspecified Vulnerability

Exploited · CISA KEV CVSS 7.8 EPSS <1%6 agency advisoriesFix available

[ Why it matters ]Priority signals

  • Exploited in the wild: on CISA's Known Exploited Vulnerabilities list since 2026-08-27

[ Description ]Official 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.

CISA: 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.

[ Fixes ]Fixes and patches

CISA required action (US federal deadline 30 Aug 2026): 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.

[ Advisories ]Government CERT advisories

  • CERT-FRCERTFR-2026-AVI-1333

    Multiple vulnerabilities in the Ubuntu Linux kernel Translated from French

    Multiple vulnerabilities have been discovered in the Ubuntu Linux kernel. Some of them allow an attacker to cause remote arbitrary code execution, privilege escalation and a breach of data confidentiality.

    CVE-2026-72407CVE-2026-72436CVE-2026-68116+1919 more CVEs
  • CERT-FRCERTFR-2026-AVI-1298

    Multiple vulnerabilities in Siemens products Translated from French

    Multiple vulnerabilities have been discovered in Siemens products. Some of them allow an attacker to cause remote arbitrary code execution, privilege escalation and remote denial of service.

    CVE-2021-41617CVE-2023-28531CVE-2023-51384+716 more CVEs
  • BSI CERT-BundWID-SEC-2026-3891

    Siemens SIMATIC S7: Multiple vulnerabilities Translated from German

    CVE-2026-46331CVE-2024-49998CVE-2025-21779+384 more CVEs
  • CERT-FRCERTFR-2026-AVI-1286

    Multiple vulnerabilities in the Ubuntu Linux kernel Translated from French

    Multiple vulnerabilities have been discovered in the Ubuntu Linux kernel. Some of them allow an attacker to cause privilege escalation, remote denial of service and a breach of data confidentiality.

    CVE-2022-27664CVE-2022-3114CVE-2022-41723+2211 more CVEs
  • CERT-FRCERTFR-2026-AVI-1252

    Multiple vulnerabilities in the Ubuntu Linux kernel Translated from French

    Multiple vulnerabilities have been discovered in the Ubuntu Linux kernel. Some of them allow an attacker to cause arbitrary code execution, privilege escalation and remote denial of service.

    CVE-2025-38724CVE-2025-54518CVE-2026-43490+1522 more CVEs
  • CERT-FRCERTFR-2026-AVI-1229

    Multiple vulnerabilities in the Ubuntu Linux kernel Translated from French

    Multiple vulnerabilities have been discovered in the Ubuntu Linux kernel. Some of them allow an attacker to cause privilege escalation, remote denial of service and a breach of data confidentiality.

    CVE-2024-27389CVE-2024-35865CVE-2024-36898+2108 more CVEs

[ References ]References