# CVE-2026-53362: Linux Kernel Unspecified

> An unprivileged user can trigger memory corruption in the Linux kernel IPv6 stack via UDPv6 sockets, potentially leading to code execution or privilege escalation.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Yes, since 27 Aug 2026 (CISA KEV)
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 4 Jul 2026
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-92007, BELL-CVE-2026-53362, DEBIAN-CVE-2026-53362, GHSA-3x6f-vm7x-cgm7, ROOT-OS-DEBIAN-12-CVE-2026-53362, ROOT-OS-UBUNTU-2404-CVE-2026-53362, UBUNTU-CVE-2026-53362

## What is CVE-2026-53362?

CVE-2026-53362 is a high-severity memory corruption vulnerability in Linux kernel, published on 4 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### 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.

Weakness: CWE-787 (Out-of-bounds Write), CWE-122 (Heap-based Buffer Overflow)

## Which versions are affected by CVE-2026-53362?

It affects 2 products.


Products: Linux kernel, Siemens Simatic S7-1500 Tm Mfp Firmware.

## How do I fix CVE-2026-53362?

Apply the vendor's patch. US federal agencies must fix it by 30 Aug 2026.

## Is CVE-2026-53362 being exploited?

Yes. Attackers have exploited CVE-2026-53362 in the wild since at least 27 Aug 2026.

Public exploit code:

- Tracking IPV6_FRAG_ESCAPE (CVE-2026-53362, CVE-2026-53366), the IPv6 fragmentation container escape (github_poc): https://github.com/suominen/ipv6_frag_escape

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-46300](https://insights.sbomify.com/CVE-2026-46300/): Linux Kernel Missing Initialization of a Variable (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53362 and fix it if it is affected.

What it is: CVE-2026-53362 is a high-severity memory corruption vulnerability in Linux kernel, published on 4 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: Yes. Attackers have exploited CVE-2026-53362 in the wild since at least 27 Aug 2026.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-53362/ (Markdown: https://insights.sbomify.com/CVE-2026-53362/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53362
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53362
- OSV: https://osv.dev/vulnerability/CVE-2026-53362

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53362/
Summaries are generated and may contain mistakes; the official description above is the record.