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VulnerabilityPublished Updated

CVE-2026-46300: Linux kernel · net: skbuff: preserve shared-frag marker during coalescing

Affects Linux kernelSource CVE Database V5

0

Public exploit available (Metasploit, Exploit-DB) · 10% EPSS · CVSS 7.8 High · fixed in f84eca5817390257cef78013d0112481c503b4a3 : patch Linux kernel as a priority.

Data as of 26 Oct 2026, 12:55 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
10.1% chance of exploitation in 30 days – higher than 95% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in f84eca5817390257cef78013d0112481c503b4a3, 3884358a9286b17f389a72b1426fc4547c23c111, 3599e6b3cc1ada96883d496a50a210d3afbb6987 +5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

t = 0 is the CVE’s publication on cve.org

  1. Disclosed: evidence found.

    CVE published 23 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  4. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

Timeline

  1. CVE ID reserved

    by kernel.org

    , 10 days before disclosure

  2. CVE published

    on cve.org

    , t = 0

  3. First Exploit-DB entry (opens in a new tab)

    Linux Kernel - Local Privilege Escalation

    , 6 days after disclosure

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ cef401de7be8c4e155c6746bfccf721a4fa5fab9, < f84eca5817390257cef78013d0112481c503b4a3
Fixed in
  • f84eca5817390257cef78013d0112481c503b4a3
LinuxLinuxAffected
  • ≥ cef401de7be8c4e155c6746bfccf721a4fa5fab9, < 3884358a9286b17f389a72b1426fc4547c23c111
Fixed in
  • 3884358a9286b17f389a72b1426fc4547c23c111
LinuxLinuxAffected
  • ≥ cef401de7be8c4e155c6746bfccf721a4fa5fab9, < 3599e6b3cc1ada96883d496a50a210d3afbb6987
Fixed in
  • 3599e6b3cc1ada96883d496a50a210d3afbb6987
LinuxLinuxAffected
  • ≥ cef401de7be8c4e155c6746bfccf721a4fa5fab9, < 760e1addc27ba1a7beb4a0a7e8b3e9ec49e7a34e
Fixed in
  • 760e1addc27ba1a7beb4a0a7e8b3e9ec49e7a34e
LinuxLinuxAffected
  • ≥ cef401de7be8c4e155c6746bfccf721a4fa5fab9, < 78bf6b6bb19541d19fbda6242e7cfe2c682763c0
Fixed in
  • 78bf6b6bb19541d19fbda6242e7cfe2c682763c0
LinuxLinuxAffected
  • ≥ cef401de7be8c4e155c6746bfccf721a4fa5fab9, < 9d3e5fd19fe1063bf607219e8562fbd567b8e8d5
Fixed in
  • 9d3e5fd19fe1063bf607219e8562fbd567b8e8d5

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.

Reports on CVE-2026-46300

References

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