In the Linux kernel, the following vulnerability has been resolved:
netfilter: revalidate bridge ports
ebt_redirect_tg() dereferences br_port_get_rcu() return without a NULL check, causing a kernel panic when the bridge port has been removed between the original hook invocation and an NFQUEUE reinject.
A mere NULL check isn't sufficient, however. As sashiko review points out userspace can not only remove the port from the bridge, it could also place the device in a different virtual device, e.g. macvlan.
If this happens, we must drop the packet, there is no way for us to reinject it into the bridge path.
Switch to _upper API, we don't need the bridge port structure. Also, this fix keeps another bug intact:
Both nfnetlink_log and nfnetlink_queue use CONFIG_BRIDGE_NETFILTER too aggressive, which prevents certain logging features when queueing in bridge family: NETFILTER_FAMILY_BRIDGE can be enabled while the old CONFIG_BRIDGE_NETFILTER cruft is off.
Fixes tag is a common ancestor, this was always broken.
| Software | From | Fixed in |
|---|---|---|
| linux / linux_kernel | 2.6.36 | 6.12.94 |
| linux / linux_kernel | 6.13 | 6.18.36 |
| linux / linux_kernel | 6.19 | 7.0.13 |
| linux / linux_kernel | 7.1-rc1 | 7.1-rc1.x |
| linux / linux_kernel | 7.1-rc2 | 7.1-rc2.x |
| linux / linux_kernel | 7.1-rc3 | 7.1-rc3.x |
| linux / linux_kernel | 7.1-rc4 | 7.1-rc4.x |
| linux / linux_kernel | 7.1-rc5 | 7.1-rc5.x |
| linux / linux_kernel | 7.1-rc6 | 7.1-rc6.x |
| linux / linux_kernel | 7.1-rc7 | 7.1-rc7.x |
A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.
CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.
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Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.
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