Critical severity · published Aug 10, 2026
CVE-2026-68123
openvswitch: fix GSO userspace truncation underflow
9.8
CVSS
0.6%
EPSS
No
On KEV
Description
In the Linux kernel, the following vulnerability has been resolved:
openvswitch: fix GSO userspace truncation underflow
OVS_ACTION_ATTR_TRUNC currently stores a delta from the original skb
length in OVS_CB(skb)->cutlen. When a later userspace action segments a
GSO skb, queue_gso_packets() reuses that delta for each smaller segment.
A segment can then reach queue_userspace_packet() with cutlen greater
than skb->len, underflowing the length passed to skb_zerocopy().
Store the maximum preserved length instead and bound each consumer
against the current skb length. Use U32_MAX as the no-truncation
sentinel so the value remains valid if skb geometry changes before a
consumer handles it.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 46% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LI
Linux · Linux
f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 before 50a6a85f3d6b1d22d8436848606cdef5d2c490b4; f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 before 2623c48cc3a8da9a1886fd8f65c0e348f4406fd6; f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 before e211b081901ffca76674082c73eeaed53524c369; f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 before a16eaaf7c0b0ccdef6166707d90ffbc6eebf6855; f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 before fbfa3ad2ad6f3a5624aba5211c46290fb98cc9dc; f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 before 100a23b1613e9218e0af654ef102352c713f0263; +3 more · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-68123
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-68123
git.kernel.org
https://git.kernel.org/stable/c/100a23b1613e9218e0af654ef102352c713f0263
git.kernel.org
https://git.kernel.org/stable/c/2623c48cc3a8da9a1886fd8f65c0e348f4406fd6
git.kernel.org
https://git.kernel.org/stable/c/4032f8ed10fcb84d41c508dfb04be96589f78dfe
git.kernel.org
https://git.kernel.org/stable/c/50a6a85f3d6b1d22d8436848606cdef5d2c490b4
git.kernel.org
https://git.kernel.org/stable/c/a16eaaf7c0b0ccdef6166707d90ffbc6eebf6855
git.kernel.org
https://git.kernel.org/stable/c/e211b081901ffca76674082c73eeaed53524c369
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