# CVE-2026-53363: xfrm: iptfs: preserve shared-frag marker in iptfs_consume_frags()

> A missing flag in Linux kernel xfrm iptfs handling can lead to memory corruption, allowing attackers to execute code or escalate privileges.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 10 Jul 2026
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2026-53363, DEBIAN-CVE-2026-53363, GHSA-7xf9-r6gc-x4cm, UBUNTU-CVE-2026-53363

## What is CVE-2026-53363?

CVE-2026-53363 is a critical memory corruption vulnerability in Linux kernel, published on 10 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

xfrm: iptfs: preserve shared-frag marker in iptfs_consume_frags()

iptfs_consume_frags() transfers paged fragments from one socket buffer
to another but fails to propagate the SKBFL_SHARED_FRAG flag. This is
the same class of bug that was fixed in skb_try_coalesce() for
CVE-2026-46300: when fragments backed by read-only page-cache pages are
merged, the marker indicating their shared nature must be preserved so
that ESP can decide correctly whether in-place encryption is safe.

Apply the same two-line fix used in skb_try_coalesce() to
iptfs_consume_frags().

## Which versions are affected by CVE-2026-53363?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-53363?

Apply the vendor's patch.

## Is CVE-2026-53363 being exploited?

There is no known exploitation of CVE-2026-53363 in the wild and no public exploit code.

## 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-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53363 and fix it if it is affected.

What it is: CVE-2026-53363 is a critical memory corruption vulnerability in Linux kernel, published on 10 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-53363 in the wild and no public exploit code.

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-2026-53363/ (Markdown: https://insights.sbomify.com/CVE-2026-53363/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53363
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53363
- OSV: https://osv.dev/vulnerability/CVE-2026-53363

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53363/
Summaries are generated and may contain mistakes; the official description above is the record.