# CVE-2026-46300: net: skbuff: preserve shared-frag marker during coalescing

> CVE-2026-46300: net: skbuff: preserve shared-frag marker during coalescing. CVSS 7.8 (CVSS 3.1), named in 2 status incident(s).

Canonical: https://rewindex.com/cve/CVE-2026-46300
Last updated: 2026-10-19T20:18:40Z

- Published: 2026-05-23 11:44 UTC · Updated: 2026-10-19 20:18 UTC · Assigner: Linux
- CVSS: 7.8 (CVSS 3.1) · Severity: High · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS: n/a
- CISA KEV: no

## Description

In the Linux kernel, the following vulnerability has been resolved: net: skbuff: preserve shared-frag marker during coalescing skb\_try\_coalesce() can attach paged frags from @from to @to.  If @from has SKBFL\_SHARED\_FRAG set, the resulting @to skb can contain the same externally-owned or page-cache-backed frags, but the shared-frag marker is currently lost. That breaks the invariant relied on by later in-place writers.  In particular, ESP input checks skb\_has\_shared\_frag() before deciding whether an uncloned nonlinear skb can skip skb\_cow\_data().  If TCP receive coalescing has moved shared frags into an unmarked skb, ESP can see skb\_has\_shared\_frag() as false and decrypt in place over page-cache backed frags. Propagate SKBFL\_SHARED\_FRAG when skb\_try\_coalesce() transfers paged frags.  The tailroom copy path does not need the marker because it copies bytes into @to's linear data rather than transferring frag descriptors.

## Affected vendors and products

- Linux: Linux
- Red Hat: NVIDIA for RHEL 10
- Red Hat: Red Hat Enterprise Linux 10
- Red Hat: Red Hat Enterprise Linux 10.0 Extended Update Support
- Red Hat: Red Hat Enterprise Linux 6
- Red Hat: Red Hat Enterprise Linux 7
- Red Hat: Red Hat Enterprise Linux 8
- Red Hat: Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
- Red Hat: Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On
- Red Hat: Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
- Red Hat: Red Hat Enterprise Linux 8.6 Telecommunications Update Service
- Red Hat: Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions
- Red Hat: Red Hat Enterprise Linux 8.8 Telecommunications Update Service
- Red Hat: Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
- Red Hat: Red Hat Enterprise Linux 9
- Red Hat: Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions
- Red Hat: Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions
- Red Hat: Red Hat Enterprise Linux 9.4 Extended Update Support
- Red Hat: Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions
- Red Hat: Red Hat Enterprise Linux 9.6 Extended Update Support
- Red Hat: Red Hat OpenShift Container Platform 4.12
- Red Hat: Red Hat OpenShift Container Platform 4.13
- Red Hat: Red Hat OpenShift Container Platform 4.14
- Red Hat: Red Hat OpenShift Container Platform 4.15
- Red Hat: Red Hat OpenShift Container Platform 4.16
- Red Hat: Red Hat OpenShift Container Platform 4.17
- Red Hat: Red Hat OpenShift Container Platform 4.18
- Red Hat: Red Hat OpenShift Container Platform 4.19
- Red Hat: Red Hat OpenShift Container Platform 4.20
- Red Hat: Red Hat OpenShift Container Platform 4.21
- Siemens: SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
- Siemens: SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
- Siemens: SIPLUS S7-1500 CPU 1518-4 PN/DP MFP

## Status incidents that name it

- 2026-05-13 21:02 UTC [Linode (Akamai): \[Fragnesia\] Linux Privilege Escalation Vulnerability](https://rewindex.com/company/linode-akamai/incidents/m3r11p4pq1zv.md) (names this CVE): “…We have completed our investigation and response to the "DirtyFrag" (CVE-2026-43500, CVE-2026-43284) and "Fragnesia" (CVE-2026-46300) vulnerabilities. We have published documentation articles with detailed guidance on available mitigations and…”
- 2026-05-08 13:40 UTC [Linode (Akamai): \[DirtyFrag\] Linux Privilege Escalation Vulnerability](https://rewindex.com/company/linode-akamai/incidents/wsvxwlyhw1t5.md) (names this CVE): “…We have completed our investigation and response to the "DirtyFrag" (CVE-2026-43500, CVE-2026-43284) and "Fragnesia" (CVE-2026-46300) vulnerabilities. We have published documentation articles with detailed guidance on available mitigations and…”

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-46300)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-46300)
- [https://git.kernel.org/stable/c/2f2b16022a2e10ca7bccfb98db5ed2ec0f72641c](https://git.kernel.org/stable/c/2f2b16022a2e10ca7bccfb98db5ed2ec0f72641c)
- [https://git.kernel.org/stable/c/3599e6b3cc1ada96883d496a50a210d3afbb6987](https://git.kernel.org/stable/c/3599e6b3cc1ada96883d496a50a210d3afbb6987)
- [https://git.kernel.org/stable/c/3884358a9286b17f389a72b1426fc4547c23c111](https://git.kernel.org/stable/c/3884358a9286b17f389a72b1426fc4547c23c111)
- [https://git.kernel.org/stable/c/3bd9e113d50034db99d7ef69fd8e5242d15e414a](https://git.kernel.org/stable/c/3bd9e113d50034db99d7ef69fd8e5242d15e414a)
- [https://git.kernel.org/stable/c/760e1addc27ba1a7beb4a0a7e8b3e9ec49e7a34e](https://git.kernel.org/stable/c/760e1addc27ba1a7beb4a0a7e8b3e9ec49e7a34e)
- [https://git.kernel.org/stable/c/78bf6b6bb19541d19fbda6242e7cfe2c682763c0](https://git.kernel.org/stable/c/78bf6b6bb19541d19fbda6242e7cfe2c682763c0)
- [https://git.kernel.org/stable/c/9d3e5fd19fe1063bf607219e8562fbd567b8e8d5](https://git.kernel.org/stable/c/9d3e5fd19fe1063bf607219e8562fbd567b8e8d5)
- [https://git.kernel.org/stable/c/f84eca5817390257cef78013d0112481c503b4a3](https://git.kernel.org/stable/c/f84eca5817390257cef78013d0112481c503b4a3)

---

_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


---
Canonical: https://rewindex.com/cve/CVE-2026-46300 · Markdown: https://rewindex.com/cve/CVE-2026-46300.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-46300 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T02:15:46.580Z