CVE-2026-23057: Linux kernel · vsock/virtio: Coalesce only linear skb
Affects Linux kernelSource GCVE Database
Not known to be exploited · fixed in 6.8.0-1057.60~22.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 14:05 UTC
Rated by Threat Radar · No CVSS score from NVD or the CNA
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.8.0-1057.60~22.04.1, 6.8.0-1059.65~22.04.1, 6.8.0-1060.63~22.04.1 +27
Exploitation evidence
Disclosed: evidence found.
CVE published 4 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
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
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 |
|---|---|---|
Ubuntu 25.10linuxpkg:deb/ubuntu/linux@6.17.0-40.40?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws@6.17.0-1019.19?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure@6.17.0-1020.20?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde@6.17.0-1017.17?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-gcppkg:deb/ubuntu/linux-gcp@6.17.0-1020.22?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle@6.17.0-1018.18?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A patch is available and should be applied to affected Linux kernel versions to ensure only linear skbs are coalesced in the vsock/virtio subsystem. The vendor advisory from Ubuntu confirms that this issue is fixed in updated kernel packages. Users should update their Linux kernel to the fixed versions as provided by their distribution.
Description
A vulnerability in the Linux kernel's vsock/virtio subsystem was resolved, involving improper coalescing of socket buffers (skbs) in the receive queue. The flaw occurs when a linear skb with spare tail room is followed by a small skb, and the kernel attempts to join them. Due to the introduction of MSG_ZEROCOPY support, the assumption that the small skb is always linear is incorrect, leading to data loss and appending uninitialized kernel memory to the linear skb. This issue affects only the loopback transport among the three virtio-based transports. A patch is available to ensure only linear skbs are coalesced.
References
- ubuntu.com/security/CVE-2026-23057 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-23057 (opens in a new tab)
- git.kernel.org/linus/0386bd321d0f95d041a7b3d7b07643411b044a96 (opens in a new tab)
- git.kernel.org/stable/c/0386bd321d0f95d041a7b3d7b07643411b044a96 (opens in a new tab)
- git.kernel.org/stable/c/568e9cd8ed7ca9bf748c7687ba6501f29d30e59f (opens in a new tab)
- git.kernel.org/stable/c/63ef9b300bd09e24c57050c5dbe68feedce42e72 (opens in a new tab)
- ubuntu.com/security/notices/USN-8278-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8289-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8296-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8296-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8289-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8278-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8393-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8440-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8499-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8570-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8594-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8604-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8605-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8570-2 (opens in a new tab)