---
title: "CVE-2026-53362: Linux Kernel Unspecified Vulnerability"
url: https://erroneo.us/security/cve/CVE-2026-53362/
description: "CVE-2026-53362 (Linux Kernel): Exploited in the wild (CISA KEV). In the Linux kernel, the following vulnerability has been resolved: ipv6: account for…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-07-04
date_modified: 2026-10-21
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-53362"
kev: true
cvss: 7.8
epss: 0.00709
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-53362: Linux Kernel Unspecified Vulnerability

**Signal:** Exploited: patch now if you run it. CISA has confirmed exploitation in the wild. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Yes, if you run Linux Kernel. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2026-08-27, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2026-08-30 ; treat that as the outer limit, not the target.
- EPSS 0.7% , percentile 53: FIRST’s model estimates a 0.7% chance of exploitation activity in the next 30 days, higher than 53% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Needs local access needed. Lower urgency for most teams unless an attacker could already run code on the machine.
- Editorial verdict: Patch this week. Linux Kernel: Five Exploited Root Bugs Added to CISA KEV — Five local root bugs, all with fixes and most with public exploits, are now confirmed exploited; get every Linux host onto a current kernel and reboot this week, container hosts, CI runners and shared servers first.

## What it is

In the Linux kernel, the following vulnerability has been resolved: ipv6: account for fraggap on the paged allocation path In ip6appenddata(), when the paged-allocation branch is taken (MSGMORE / NETIFFSG / 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 skbsharedinfo. An unprivileged user can trigger this via a UDPv6 socket using MSGMORE together with MSGSPLICEPAGES. The bad accounting was introduced by commit 773ba4fe9104 ("ipv6: avoid partial copy for zc"). Before commit ce650a166335 ("udp6: Fix ip6appenddata()'s handling of MSGSPLICEPAGES"), the negative copy value caused -EINVAL to be returned. That later commit allowed MSGSPLICEPAGES 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 MSGSPLICEPAGES case, remove the MSGSPLICEPAGES exception from the negative copy check.

## Affected products (CVE record)

- Linux Linux: 773ba4fe9104a64a54d1c00f0fb6ffb95def2b03 < 14200d435af9a9eeb444f529fc2f689a236b7962, 773ba4fe9104a64a54d1c00f0fb6ffb95def2b03 < 65fb14cbebb0cd0eff903a22d33537ddc8b95769, 773ba4fe9104a64a54d1c00f0fb6ffb95def2b03 < 46f201f8b4c39633a1fa3dc12459f506d470993d, 773ba4fe9104a64a54d1c00f0fb6ffb95def2b03 < 6374fb9edf72c67a118a2c214a0dddd04c921e0a, 773ba4fe9104a64a54d1c00f0fb6ffb95def2b03 < e9eacf19281ea2498b36291b56c9606118c2d74e, 773ba4fe9104a64a54d1c00f0fb6ffb95def2b03 < 736b380e28d0480c7bc3e022f1950f31fe53a7c5
- Linux Linux: 6.0

## Severity

- Linux CVSS 3.1: 7.8 `CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`

## Exploitation

- CISA KEV: added 2026-08-27; federal due date 2026-08-30. Known ransomware use: Unknown.
- CISA 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.
- CISA SSVC assessment: exploitation active , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.71% probability of exploitation activity in the next 30 days; percentile 53.

## Sources

- [Listed in CISA KEV notes (git.kernel.org)](https://git.kernel.org/stable/c/14200d435af9a9eeb444f529fc2f689a236b7962)
- [Listed in CISA KEV notes (git.kernel.org)](https://git.kernel.org/stable/c/65fb14cbebb0cd0eff903a22d33537ddc8b95769)
- [Listed in CISA KEV notes (git.kernel.org)](https://git.kernel.org/stable/c/46f201f8b4c39633a1fa3dc12459f506d470993d)
- [Listed in CISA KEV notes (git.kernel.org)](https://git.kernel.org/stable/c/6374fb9edf72c67a118a2c214a0dddd04c921e0a)
- [Listed in CISA KEV notes (git.kernel.org)](https://git.kernel.org/stable/c/e9eacf19281ea2498b36291b56c9606118c2d74e)
- [Listed in CISA KEV notes (git.kernel.org)](https://git.kernel.org/stable/c/736b380e28d0480c7bc3e022f1950f31fe53a7c5)
- [CVE.org record CVE-2026-53362](https://www.cve.org/CVERecord?id=CVE-2026-53362)
- [NVD entry CVE-2026-53362](https://nvd.nist.gov/vuln/detail/CVE-2026-53362)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-53362)
- [Listed in CISA KEV notes (cisa.gov)](https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk)
- [Listed in CISA KEV notes (cisa.gov)](https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk)
- [cert-portal.siemens.com](https://cert-portal.siemens.com/productcert/html/ssa-784472.html)

---
Source page: https://erroneo.us/security/cve/CVE-2026-53362/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt