Vulnerability · CVE-2026-53362

Linux Kernel Unspecified Vulnerability

Published Jul 4, 2026 · catalog updated Oct 15, 2026 · Linux Kernel

Patch now

CVE-2026-53362 is in the CISA known-exploited catalog, due Aug 30, 2026. Confirm Linux Kernel against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Gaps on this record

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Severity: High7.8
Known exploitation: CISA KEV and VulnCheck KEV
EPSS: 0.71%
Remediation: Remediation guidance
Affected products: cpe linux/linux kernel · cpe siemens/simatic s7-1500 tm mfp firmware · vendor Linux Kernel · vendor Linux Linux

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.

Are you affected?

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cpe linux/linux kernelversion unspecified
cpe siemens/simatic s7-1500 tm mfp firmwareversion unspecified
vendor Linux Kernelversion unspecified
vendor Linux Linuxversion unspecified

How to fix CVE-2026-53362

Recommended remediation
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. CISA due date Aug 30, 2026.
Official advisories

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2026-53362 is in the CISA known-exploited catalog, due Aug 30, 2026. Confirm Linux Kernel against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Affected version ranges are not on this record. 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.

What should an analyst verify?

CWE-122: Heap-based Buffer Overflow; CWE-787: Out-of-bounds Write. EPSS 0.71%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

Jul 4, 2026 · Catalog
Detected
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 + fragg
Aug 27, 2026 · CISA KEV
Known exploited
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
Aug 28, 2026 · Catalog
Updated
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 + fragg
Aug 30, 2026 · CISA KEV
Remediation due
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
Oct 15, 2026 · NIST NVD
Updated
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 + fragg
Oct 15, 2026 · NIST NVD
Updated
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 + fragg

Sources

CIRCL Vulnerability LookupVulnerability recordCVE-2026-53362
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 = f
vulnerability.circl.lu
CISA KEVConfirmed exploitationCVE-2026-53362
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.
cisa.gov
CVE.orgVulnerability recordCVE-2026-53362
Official CVE identifier
cve.org
FIRST EPSSExploitation probabilityCVE-2026-53362
30-day exploitation probability 0.7%
first.org
NIST NVDVulnerability recordCVE-2026-53362
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
nvd.nist.gov
VulnCheck KEVConfirmed exploitationCVE-2026-53362
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.
vulncheck.com

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

Priority score

48/100

Evidence confidence: Very high

CISA lists this vulnerability as known to be exploited.

Confirmed exploitation30/30
EPSS probability1/20
CVSS severity12/15
Public exploit0/10
Internet exposure0/10
Product prevalence5/5
Threat research0/5

Decision signals

Four separate signals — do not infer one from another.

High

CVSS severity
7.8 v3.1
Technical impact. Separate from exploitation likelihood.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS probability
0.71% · p52.59%
Estimated probability of exploitation within 30 days (FIRST).
Known exploitation
Yes · CISA KEV and VulnCheck KEV
CISA KEV since Aug 27, 2026. Ransomware use: Unknown.
Patch availability
Remediation guidance
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.

Stacks

Linux

Weakness

CWE-122
Heap-based Buffer Overflow
MITRE definition
CWE-787
Out-of-bounds Write
MITRE definition

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