CVE-2026-46300

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.

CVSS v3.1 Score

7.8

HIGH

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

EPSS — Exploit Prediction

0.0001

Probability of exploitation

0.02%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-787 Out-of-bounds Write

Affected Products

Vendor	Product	Versions
linux	linux_kernel	3.9 — 5.10.257
linux	linux_kernel	5.11 — 5.15.208
linux	linux_kernel	5.16 — 6.1.174
linux	linux_kernel	6.2 — 6.6.141
linux	linux_kernel	6.7 — 6.12.91
linux	linux_kernel	6.13 — 6.18.33
linux	linux_kernel	6.19 — 7.0.10
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All

References

Advisories & Patches

https://git.kernel.org/stable/c/2f2b16022a2e10ca7bccfb98db5ed2ec0f72641c https://git.kernel.org/stable/c/3599e6b3cc1ada96883d496a50a210d3afbb6987 https://git.kernel.org/stable/c/3884358a9286b17f389a72b1426fc4547c23c111 https://git.kernel.org/stable/c/3bd9e113d50034db99d7ef69fd8e5242d15e414a https://git.kernel.org/stable/c/760e1addc27ba1a7beb4a0a7e8b3e9ec49e7a34e https://git.kernel.org/stable/c/78bf6b6bb19541d19fbda6242e7cfe2c682763c0 https://git.kernel.org/stable/c/9d3e5fd19fe1063bf607219e8562fbd567b8e8d5 https://git.kernel.org/stable/c/f84eca5817390257cef78013d0112481c503b4a3

Other References

http://www.openwall.com/lists/oss-security/2026/05/13/5 http://www.openwall.com/lists/oss-security/2026/05/21/11 http://www.openwall.com/lists/oss-security/2026/05/21/12 http://www.openwall.com/lists/oss-security/2026/05/21/13

Frequently Asked Questions

What is CVE-2026-46300? +

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. It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2026-46300? +

CVE-2026-46300 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0001, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-46300? +

CVE-2026-46300 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-46300? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-3298

The method "sock_recvfrom_into()" of "asyncio.ProacterEventLoop" (Windows only) was missing a boundary check for the data buffer when using nbytes parameter. …

CVE-2026-40489

editorconfig-core-c is an EditorConfig core library for use by plugins supporting EditorConfig parsing. Versions up to and including 0.12.10 have …

CVE-2025-3154

Out-of-bounds array write in Xpdf 4.05 and earlier, triggered by an invalid VerticesPerRow value in a PDF shading dictionary.

CVE-2025-4640

Out-of-bounds Write vulnerability in PointCloudLibrary pcl allows Overflow Buffers. Since version 1.14.0, PCL by default uses a zlib installation from …

CVE-2025-5688

We have identified a buffer overflow issue allowing out-of-bounds write when processing LLMNR or mDNS queries with very long DNS …

CVE-2025-49848

An Out-of-bounds Write vulnerability exists within the parsing of PRJ files. The issues result from the lack of proper validation …