HIGH · CVSS 7.8 CISA Known Exploited Vulnerability

CVE-2026-53362

Linux Kernel Unspecified Vulnerability

Linux Kernel

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 ca

CVSS
7.8
HIGH
EPSS
0.5%
30-day exploitation
Ransomware groups
0
recorded exploiting
Published
4 Jul 2026
CWE-787, CWE-122

Exploitation status

CISA Known Exploited Vulnerabilities

Listed by CISA on 27 August 2026. US federal agencies were required to remediate it by 30 August 2026.

EPSS — exploitation probability

FIRST puts the probability of exploitation activity in the next 30 days at 0.5%, which is higher than 42.5% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.

CVSS vector

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

Frequently asked questions

Is CVE-2026-53362 being exploited by ransomware groups?

No ransomware group in this database is currently recorded as exploiting CVE-2026-53362.

What does CVE-2026-53362 affect?

CVE-2026-53362 affects Linux Kernel. 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 ca

How severe is CVE-2026-53362?

CVE-2026-53362 is rated HIGH with a CVSS base score of 7.8. EPSS puts the probability of exploitation in the next 30 days at 0.5%, higher than 42.5% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 30 August 2026.

How should organisations respond to CVE-2026-53362?

Apply the vendor patch for Linux Kernel as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.