TUNderflow

TUNderflow CVE-2026-81000 Writeup !WARNING The PoC is provided solely to help defenders, maintainers, and authorized security teams validate patches, mitigations, detections, and exposure on systems they own or are explicitly authorized to test. You are solely responsible for ensuring that your u...

Astra Linux – Vulnerability found in Linux 5.10, Linux 6.1, Linux, Linux 5.15

In the Linux kernel, the following vulnerability has been resolved: net: openvswitch: Fix Use-After-Free in ovsctexit Since kfreercu, which is called during the hlistforeachentryrcu traversal of ovsctlimitexit, is not part of the RCU read critical section, it is possible that the RCU grace period...

Linux Distros Unpatched Vulnerability : CVE-2026-81000

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available. - net: tun: bound receive headroom tungetuser uses tun-align both as skb headroom and when choosing how much packet data to keep linear. OVS can propagate an...

CVE-2026-81000

In the Linux kernel, the following vulnerability has been resolved: net: tun: bound receive headroom tungetuser uses tun-align both as skb headroom and when choosing how much packet data to keep linear. OVS can propagate an oversized headroom request from another port to TUN or TAP. When align is...

AZL-100232 CVE-2026-81000 affecting package kernel 6.6.152.1-1

In the Linux kernel, the following vulnerability has been resolved: net: tun: bound receive headroom tungetuser uses tun-align both as skb headroom and when choosing how much packet data to keep linear. OVS can propagate an oversized headroom request from another port to TUN or TAP. When align is...

DEBIAN-CVE-2026-81000

In the Linux kernel, the following vulnerability has been resolved: net: tun: bound receive headroom tungetuser uses tun-align both as skb headroom and when choosing how much packet data to keep linear. OVS can propagate an oversized headroom request from another port to TUN or TAP. When align is...

DEBIAN-CVE-2026-80977

In the Linux kernel, the following vulnerability has been resolved: net: skbuff: don't touch shared zerocopy state in skbtxerror skbtxerror completes the zerocopy uarg and clears SKBFLALLZEROCOPY, and skbzcopydowngrademanaged clears SKBFLMANAGEDFRAGREFS. Both live in skbshinfo, which every clone...

CVE-2026-81000

In the Linux kernel, the following vulnerability has been resolved: net: tun: bound receive headroom tungetuser uses tun-align both as skb headroom and when choosing how much packet data to keep linear. OVS can propagate an oversized headroom request from another port to TUN or TAP. When align is...

CVE-2026-81000 net: tun: bound receive headroom

In the Linux kernel, the following vulnerability has been resolved: net: tun: bound receive headroom tungetuser uses tun-align both as skb headroom and when choosing how much packet data to keep linear. OVS can propagate an oversized headroom request from another port to TUN or TAP. When align is...

CVE-2026-81000

CVE-2026-81000 affects the Linux kernel TUN/TAP driver . The root cause is an integer underflow in tun_get_user(): when Open vSwitch (OVS) propagates an oversized headroom request from another port, SKB_MAX_HEAD(align) underflows, causing tun_alloc_skb() to place skb->data outside the allocate...

CVE-2026-81000 net: tun: bound receive headroom

In the Linux kernel, the following vulnerability has been resolved: net: tun: bound receive headroom tungetuser uses tun-align both as skb headroom and when choosing how much packet data to keep linear. OVS can propagate an oversized headroom request from another port to TUN or TAP. When align is...

EUVD-2026-76323

In the Linux kernel, the following vulnerability has been resolved: net: tun: bound receive headroom tungetuser uses tun-align both as skb headroom and when choosing how much packet data to keep linear. OVS can propagate an oversized headroom request from another port to TUN or TAP. When align is...

CVE-2026-81000

In the Linux kernel, the following vulnerability has been resolved: net: tun: bound receive headroom tungetuser uses tun-align both as skb headroom and when choosing how much packet data to keep linear. OVS can propagate an oversized headroom request from another port to TUN or TAP. When align is...

CVE-2026-80977 net: skbuff: don't touch shared zerocopy state in skb_tx_error()

In the Linux kernel, the following vulnerability has been resolved: net: skbuff: don't touch shared zerocopy state in skbtxerror skbtxerror completes the zerocopy uarg and clears SKBFLALLZEROCOPY, and skbzcopydowngrademanaged clears SKBFLMANAGEDFRAGREFS. Both live in skbshinfo, which every clone...

CVE-2026-81000: Undefined Security Weakness

In the Linux kernel, the following vulnerability has been resolved: net: tun: bound receive headroom tungetuser uses tun-align both as skb headroom and when choosing how much packet data to keep linear. OVS can propagate an oversized headroom request from another port to TUN or TAP. When align is...

PT-2026-90130

In the Linux kernel, the following vulnerability has been resolved: net: tun: bound receive headroom tun get user uses tun-align both as skb headroom and when choosing how much packet data to keep linear. OVS can propagate an oversized headroom request from another port to TUN or TAP. When align ...

EulerOS 2.0 SP12 : lxc (EulerOS-SA-2026-3282)

According to the versions of the lxc packages installed, the EulerOS installation on the remote host is affected by the following vulnerabilities : lxc is a Linux container runtime. In the setuid helper lxc-user-nic, the delete path contains a logic flaw in the findline function that allows an...

Astra Linux – Vulnerability found in Linux 5.10, Linux 6.1, Linux, Linux 5.15

In the Linux kernel, the following vulnerabilities have been resolved: openvswitch: Use RCU protection in ovsvportcmdfillinfo. ovsvportcmdfillinfo can be called without RTNL or RCU. Use RCU protection and devnetrcu to avoid potential UAF Use-After-Free errors...

Astra Linux – Vulnerability found in Linux 5.10, Linux 6.1

In the Linux kernel, the following vulnerability has been resolved: netfilter: nfconncount – increased the connection cleanup limit to 64. After the optimization to perform only one garbage collection per jiffy, a new problem emerged. If more than 8 new connections are tracked per jiffy, the list...

Astra Linux – Vulnerability in Linux 6.1

In the Linux kernel, the following vulnerability has been resolved: OpenVSwitch: fixed the issue where locking occurred when trying to unregister a netdev with a carrier. The commit in the “fixes” tag attempted to fix this issue through the following sequence of calls: dooutput → ovsvportsend →...