CVE-2026-46300: Linux kernel · net: skbuff: preserve shared-frag marker during coalescing
Affects Linux kernelSource CVE Database V5
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
- 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:HExploitation evidence
t = 0 is the CVE’s publication on cve.org
Disclosed: evidence found.
CVE published 23 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: evidence found.
1 Metasploit module · 1 Exploit-DB entry, 6 days after disclosure
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
Timeline
CVE ID reserved
by kernel.org
, 10 days before disclosure
CVE published
on cve.org
, t = 0
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
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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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
- git.kernel.org/stable/c/3599e6b3cc1ada96883d496a50a210d3afbb6987 (opens in a new tab)
- git.kernel.org/stable/c/2f2b16022a2e10ca7bccfb98db5ed2ec0f72641c (opens in a new tab)
- git.kernel.org/stable/c/9d3e5fd19fe1063bf607219e8562fbd567b8e8d5 (opens in a new tab)
- git.kernel.org/stable/c/78bf6b6bb19541d19fbda6242e7cfe2c682763c0 (opens in a new tab)
- git.kernel.org/stable/c/760e1addc27ba1a7beb4a0a7e8b3e9ec49e7a34e (opens in a new tab)
- git.kernel.org/stable/c/3bd9e113d50034db99d7ef69fd8e5242d15e414a (opens in a new tab)
- git.kernel.org/stable/c/3884358a9286b17f389a72b1426fc4547c23c111 (opens in a new tab)
- git.kernel.org/stable/c/f84eca5817390257cef78013d0112481c503b4a3 (opens in a new tab)
- openwall.com/lists/oss-security/2026/05/13/5 (opens in a new tab)
- openwall.com/lists/oss-security/2026/05/21/11 (opens in a new tab)
- openwall.com/lists/oss-security/2026/05/21/12 (opens in a new tab)
- openwall.com/lists/oss-security/2026/05/21/13 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-46300 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2477015 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-46300.json (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19540 (opens in a new tab)
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- access.redhat.com/errata/RHSA-2026:21656 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:23245 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:21702 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:23240 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:20299 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19569 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19705 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:20593 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:20054 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:20129 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19568 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19666 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:23470 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:20130 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:20051 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19521 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:23471 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:23469 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:24814 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:23468 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19664 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19711 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19875 (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-082556.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-019113.html (opens in a new tab)