CVE-2026-53362: Linux Kernel Unspecified Vulnerability

CISA Known Exploited Vulnerabilities

Name

Linux Kernel Unspecified Vulnerability

Vendor

Linux

Product

Kernel

Added to the catalog

2026-08-27

Due date for US federal agencies

2026-08-30

Catalog version

2026.10.30

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.

Required action (CISA)

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.

Ransomware use: CISA does not mark known use of this vulnerability in ransomware campaigns.

Links in CISA's notes

• https://git.kernel.org/stable/c/14200d435af9a9eeb444f529fc2f689a236b7962
• https://git.kernel.org/stable/c/65fb14cbebb0cd0eff903a22d33537ddc8b95769
• https://git.kernel.org/stable/c/46f201f8b4c39633a1fa3dc12459f506d470993d
• https://git.kernel.org/stable/c/6374fb9edf72c67a118a2c214a0dddd04c921e0a
• https://git.kernel.org/stable/c/e9eacf19281ea2498b36291b56c9606118c2d74e
• https://git.kernel.org/stable/c/736b380e28d0480c7bc3e022f1950f31fe53a7c5
• https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
• https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
• https://nvd.nist.gov/vuln/detail/CVE-2026-53362

Read on 2026-11-02T23:39:54.475Z under licence cisa-kev-cc0@b0067899 from https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

NVD analysis

Status

Analyzed

Published

2026-07-04T12:17:02.113

Last modified

2026-10-15T13:46:55.187

Weaknesses

CWE-787, CWE-122

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.

References

• https://git.kernel.org/stable/c/14200d435af9a9eeb444f529fc2f689a236b7962 (Patch)
• https://git.kernel.org/stable/c/46f201f8b4c39633a1fa3dc12459f506d470993d (Patch)
• https://git.kernel.org/stable/c/6374fb9edf72c67a118a2c214a0dddd04c921e0a (Patch)
• https://git.kernel.org/stable/c/65fb14cbebb0cd0eff903a22d33537ddc8b95769 (Patch)
• https://git.kernel.org/stable/c/736b380e28d0480c7bc3e022f1950f31fe53a7c5 (Patch)
• https://git.kernel.org/stable/c/e9eacf19281ea2498b36291b56c9606118c2d74e (Patch)
• https://cert-portal.siemens.com/productcert/html/ssa-784472.html (Third Party Advisory)
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-53362 (US Government Resource)

This product uses the NVD API but is not endorsed or certified by the NVD.

Read on 2026-11-02T23:42:31.494Z under licence nvd-api-terms-of-use@ff2a5288 from https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-53362

CVE record

Title (CNA)

ipv6: account for fraggap on the paged allocation path

Assigner

Linux

State

PUBLISHED

Published

2026-07-04T11:56:35.864Z

Updated

2026-10-15T01:23:25.441Z

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.

References

• https://git.kernel.org/stable/c/14200d435af9a9eeb444f529fc2f689a236b7962
• https://git.kernel.org/stable/c/65fb14cbebb0cd0eff903a22d33537ddc8b95769
• https://git.kernel.org/stable/c/46f201f8b4c39633a1fa3dc12459f506d470993d
• https://git.kernel.org/stable/c/6374fb9edf72c67a118a2c214a0dddd04c921e0a
• https://git.kernel.org/stable/c/e9eacf19281ea2498b36291b56c9606118c2d74e
• https://git.kernel.org/stable/c/736b380e28d0480c7bc3e022f1950f31fe53a7c5

Read on 2026-11-03T02:20:30.907Z under licence cve-terms-of-use@81bfa2f3 from https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/53xxx/CVE-2026-53362.json

Defensive techniques (MITRE D3FEND)

D3FEND maps these defensive techniques to the weakness (CWE) that NVD lists for this CVE, through the digital artifacts the weakness affects. D3FEND does not say they stop this vulnerability.

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