CVE-2026-46300: Linux kernel · net: skbuff: preserve shared-frag marker during coalescing
Affects Linux kernelSource GCVE Database
Public exploit available (Metasploit, Exploit-DB) · 10% EPSS · CVSS 7.8 High · fixed in 5.15.0-1109.116~20.04.1 : patch Linux kernel as a priority.
Data as of 26 Oct 2026, 14:05 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.
- Patch
- Available – fixed in 5.15.0-1109.116~20.04.1, 5.15.0-1114.123~20.04.1, 5.15.0-1109.118~20.04.1 +83
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.
Patches and advisories
- ubuntu.com/security/notices/USN-8370-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8371-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8373-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8374-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8388-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8393-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8426-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8426-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8440-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8388-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8461-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8462-1 (opens in a new tab)
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-ibmpkg:deb/ubuntu/linux-ibm?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
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.
References
- ubuntu.com/security/CVE-2026-46300 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-46300 (opens in a new tab)
- github.com/v12-security/pocs/tree/main/fragnesia (opens in a new tab)
- openwall.com/lists/oss-security/2026/05/21/11 (opens in a new tab)
- git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=f84eca5817390257cef78013d0112481c503b4a3 (opens in a new tab)
- lore.kernel.org/all/agRfuVOeMI5pbHhY@v4bel/ (opens in a new tab)
- ubuntu.com/security/notices/USN-8370-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8371-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8373-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8374-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8388-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8393-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8426-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8426-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8440-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8388-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8461-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8462-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8489-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8497-1 (opens in a new tab)