CVE-2026-31684
Vulnerability Summary
Timeline
Description
In the Linux kernel, the following vulnerability has been resolved: net: sched: act_csum: validate nested VLAN headers tcf_csum_act() walks nested VLAN headers directly from skb->data when an skb still carries in-payload VLAN tags. The current code reads vlan->h_vlan_encapsulated_proto and then pulls VLAN_HLEN bytes without first ensuring that the full VLAN header is present in the linear area. If only part of an inner VLAN header is linearized, accessing h_vlan_encapsulated_proto reads past the linear area, and the following skb_pull(VLAN_HLEN) may violate skb invariants. Fix this by requiring pskb_may_pull(skb, VLAN_HLEN) before accessing and pulling each nested VLAN header. If the header still is not fully available, drop the packet through the existing error path.
CVSS Metrics
- v3.1•MEDIUM•Score: 5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS Trends
Current EPSS score: 0.12%• Percentile: 2%
Affected Systems
- chainguard•linux-aws-6.18
< 6.18.31-r0
- chainguard•linux-azure-6.18
< 6.18.24-r1 | < 6.18.31-r0
- chainguard•linux-gcp-6.18
< 6.18.31-r0
- chainguard•linux-qemu-6.18
< 6.18.24-r3
- chainguard•linux-vmware-6.18
< 6.18.31-r0
- debian•linux
< 5.10.259-1 | < 6.1.176-1 | < 6.12.85-1 | < 6.19.14-1
- debian•linux-6.1
< 6.1.176-1~deb11u1
- ubuntu•linux
all | < 5.15.0-186.196 | < 6.8.0-136.136 | all
- ubuntu•linux-allwinner-5.19
all
- ubuntu•linux-aws
all | < 5.15.0-1112.119 | < 6.8.0-1061.64 | all
- ubuntu•linux-aws-5.0
all
- ubuntu•linux-aws-5.11
all
- ubuntu•linux-aws-5.13
all
- ubuntu•linux-aws-5.15
< 5.15.0-1112.119~20.04.1
- ubuntu•linux-aws-5.19
all
- ubuntu•linux-aws-5.3
all
- ubuntu•linux-aws-5.4
all
- ubuntu•linux-aws-5.8
all
- ubuntu•linux-aws-6.14
all
- ubuntu•linux-aws-6.17
all
- ubuntu•linux-aws-6.2
all
- ubuntu•linux-aws-6.5
all
- ubuntu•linux-aws-6.8
< 6.8.0-1061.64~22.04.1
- ubuntu•linux-aws-fips
all | < 5.15.0-1112.119+fips1 | < 6.8.0-1061.64+fips1
- ubuntu•linux-azure
all | all | < 5.15.0-1117.126 | < 6.8.0-1063.71 | all
- ubuntu•linux-azure-5.11
all
- ubuntu•linux-azure-5.13
all
- ubuntu•linux-azure-5.15
< 5.15.0-1117.126~20.04.1
- ubuntu•linux-azure-5.19
all
- ubuntu•linux-azure-5.3
all
- ubuntu•linux-azure-5.4
all
- ubuntu•linux-azure-5.8
all
- ubuntu•linux-azure-6.11
all
- ubuntu•linux-azure-6.14
all
- ubuntu•linux-azure-6.17
all
- ubuntu•linux-azure-6.2
all
- ubuntu•linux-azure-6.5
all
- ubuntu•linux-azure-6.8
< 6.8.0-1063.71~22.04.1
- ubuntu•linux-azure-edge
all
- ubuntu•linux-azure-fde
all | < 5.15.0-1117.126 | < 6.8.0-1062.69 | all | all
- ubuntu•linux-azure-fde-5.15
< 5.15.0-1117.126~20.04.2
- ubuntu•linux-azure-fde-5.19
all
- ubuntu•linux-azure-fde-6.14
all
- ubuntu•linux-azure-fde-6.2
all
- ubuntu•linux-azure-fde-6.8
< 6.8.0-1062.69~22.04.1
- ubuntu•linux-azure-fde-7.0
all
- ubuntu•linux-azure-fips
all | < 5.15.0-1117.126+fips1 | < 6.8.0-1063.71+fips2
- ubuntu•linux-azure-nvidia
all
- ubuntu•linux-azure-nvidia-6.14
all
- ubuntu•linux-bluefield
all | all | < 5.15.0-1096.98 | < 6.8.0-1028.33
Showing first 50 affected entries in server-rendered view.
References (38)
- https://git.kernel.org/stable/c/a69738efea0996d05a3c7d2178551b891744df1b
- https://git.kernel.org/stable/c/ec4930979b3f7bbeb7af5744599fc6603a4dba62
- https://git.kernel.org/stable/c/3d165d975305cf76ff0b10a3c798fb31e5f5f9a5
- https://git.kernel.org/stable/c/c842743d073bdd683606cb414eb0ca84465dd834
- https://git.kernel.org/stable/c/eb3765b90eb8f2a3d6310a80c14a9e57ec4267a2
- https://git.kernel.org/stable/c/0410c619e86551677fb79887a38eccad3f5a0725
- https://git.kernel.org/stable/c/886469b6455611a511aa6013e957e15e50577513
- https://git.kernel.org/stable/c/46c07ad50fa2f4ba7663ee1b72b75ad7ad45cf09
- https://ubuntu.com/security/CVE-2026-31684
- https://www.cve.org/CVERecord?id=CVE-2026-31684
- https://git.kernel.org/linus/c842743d073bdd683606cb414eb0ca84465dd834
- https://ubuntu.com/security/notices/USN-8567-1
- https://ubuntu.com/security/notices/USN-8574-1
- https://ubuntu.com/security/notices/USN-8575-1
- https://ubuntu.com/security/notices/USN-8576-1
- https://ubuntu.com/security/notices/USN-8574-2
- https://ubuntu.com/security/notices/USN-8595-1
- https://ubuntu.com/security/notices/USN-8596-1
- https://ubuntu.com/security/notices/USN-8575-2
- https://ubuntu.com/security/notices/USN-8576-2
- https://ubuntu.com/security/notices/USN-8597-1
- https://ubuntu.com/security/notices/USN-8595-2
- https://ubuntu.com/security/notices/USN-8606-1
- https://ubuntu.com/security/notices/USN-8607-1
- https://ubuntu.com/security/notices/USN-8608-1
- https://ubuntu.com/security/notices/USN-8609-1
- https://ubuntu.com/security/notices/USN-8575-3
- https://ubuntu.com/security/notices/USN-8610-1
- https://ubuntu.com/security/notices/USN-8574-3
- https://ubuntu.com/security/notices/USN-8595-3
- https://ubuntu.com/security/notices/USN-8619-1
- https://ubuntu.com/security/notices/USN-8620-1
- https://ubuntu.com/security/notices/USN-8620-2
- https://ubuntu.com/security/notices/USN-8620-3
- https://ubuntu.com/security/notices/USN-8620-4
- https://security-tracker.debian.org/tracker/CVE-2026-31684
- https://ubuntu.com/security/notices/USN-8665-1
- https://ubuntu.com/security/notices/USN-8668-1