CyberSecBulletin
CVE-2026-68123NVD status: Received

Linux: Integer Underflow (Wrap or Wraparound)

Published Updated By the CyberSecBulletin desk

CVE-2026-68123 is a critical-severity integer underflow (wrap or wraparound) vulnerability in Linux, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 50a6a85f3d6b1d22d8436848606cdef5d2c490b4, 2623c48cc3a8da9a1886fd8f65c0e348f4406fd6, e211b081901ffca76674082c73eeaed53524c369 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.55% chance of exploitation within 30 days, which is low compared with other CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Update Linux to 50a6a85f3d6b1d22d8436848606cdef5d2c490b4 or 2623c48cc3a8da9a1886fd8f65c0e348f4406fd6 or e211b081901ffca76674082c73eeaed53524c369 or a16eaaf7c0b0ccdef6166707d90ffbc6eebf6855, whichever matches your release line, or a later version.
  2. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxf2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 up to, but not including, 50a6a85f3d6b1d22d8436848606cdef5d2c490b4; f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 up to, but not including, 2623c48cc3a8da9a1886fd8f65c0e348f4406fd6; f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 up to, but not including, e211b081901ffca76674082c73eeaed53524c369; f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 up to, but not including, a16eaaf7c0b0ccdef6166707d90ffbc6eebf6855; f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 up to, but not including, fbfa3ad2ad6f3a5624aba5211c46290fb98cc9dc; f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 up to, but not including, 100a23b1613e9218e0af654ef102352c713f0263; f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 up to, but not including, ea85dbcbe8d4056ecb54352f97743d138ea4c407; f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 up to, but not including, 4032f8ed10fcb84d41c508dfb04be96589f78dfe; and 1 more ranges50a6a85f3d6b1d22d8436848606cdef5d2c490b4, 2623c48cc3a8da9a1886fd8f65c0e348f4406fd6, e211b081901ffca76674082c73eeaed53524c369, a16eaaf7c0b0ccdef6166707d90ffbc6eebf6855, fbfa3ad2ad6f3a5624aba5211c46290fb98cc9dc, 100a23b1613e9218e0af654ef102352c713f0263

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.

Official 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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Integer Underflow (Wrap or Wraparound)

The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result.

More Integer Underflow (Wrap or Wraparound) vulnerabilities (CWE-191)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Integer Underflow (Wrap or Wraparound) vulnerabilities

Spotted an error? Tell us.