Linux Kernel Network and Event Handling

A race condition exists in the Linux kernel's perf subsystem where __perf_event_overflow() can execute with only preemption disabled (rather than IRQs disabled) on software events, creating a window for concurrent execution with perf_event_exit_event() and related cleanup functions. This race condition allows the overflow handler to access kernel structures (such as BPF programs) that are being freed concurrently, potentially leading to use-after-free conditions, memory corruption, or privilege escalation. The vulnerability affects multiple stable Linux kernel versions and has patches available across multiple kernel branches (6.12.77, 6.19.7, 7.0-rc2, and others as indicated by the git commit references).

A use-after-free vulnerability exists in the Linux kernel's netfilter nf_tables subsystem where a set element can be published and removed without waiting for RCU grace period completion, allowing concurrent RCU readers to access freed memory. This affects all Linux kernel versions across multiple stable branches (4.10 and later) as indicated by the CPE cpe:2.3:a:linux:linux:*:*:*:*:*:*:*:*. An attacker with local access to manipulate netfilter rules could trigger information disclosure or denial of service by exploiting the race condition during batch insertion of elements into a full netfilter set.

Linux kernel netfilter xt_IDLETIMER subsystem crashes when revision 0 rules reuse ALARM-type timer labels created by revision 1, triggering mod_timer() on an uninitialized timer_list. Affects Linux kernel 5.7+ through 6.19.x series. Local authenticated attackers with CAP_NET_ADMIN (PR:L) can cause kernel panic on systems with panic_on_warn=1, achieving high-severity local denial of service or potential privilege escalation via kernel memory corruption. EPSS score is very low (0.02%, 4th percentile) indicating minimal observed exploitation likelihood. No public exploit code identified at time of analysis.

A resource management flaw in the Linux kernel's netfilter nf_tables subsystem fails to properly iterate over all pending catchall elements during transaction processing, leading to incomplete cleanup when a map holding catchall elements is destroyed. This affects Linux kernel versions across multiple stable branches and can result in memory corruption, information disclosure, or denial of service when crafted netfilter rule transactions are processed. The vulnerability is not known to be actively exploited in the wild, but the presence of multiple stable branch patches and specific affected kernel versions indicates kernel maintainers have treated this as a material flaw requiring coordinated remediation.

A use-after-free race condition exists in the Linux kernel's macvlan driver within the macvlan_common_newlink() error handling path. When a macvlan device creation fails after the network device becomes visible to the RCU (Read-Copy-Update) subsystem, the caller's subsequent free_netdev(dev) can race with ongoing packet forwarding operations, causing kernel memory corruption and potential information disclosure. This vulnerability affects Linux kernel versions 5.10 through 6.19 and later, and while no public exploit exists, the issue is reproducible via crafted netlink commands that trigger concurrent device creation and packet transmission.

A race condition exists in the Linux kernel's io_uring subsystem where task work flags can be manipulated on stale ring memory during concurrent ring resize operations when DEFER_TASKRUN or SETUP_TASKRUN modes are enabled. This vulnerability affects Linux kernel versions including 6.13, 6.18.19, 6.19.9, and 7.0-rc4, and could allow an attacker with local code execution capabilities to cause information disclosure or kernel memory corruption. The vulnerability has been patched across multiple stable kernel versions as evidenced by available git commits, though no active KEV status or EPSS score has been published.

A NULL pointer dereference vulnerability exists in the Linux kernel's TEQL (Trivial Ethernet Queue Limiting) network scheduler when transmitting through tunnel slave devices, particularly gretap tunnels. The vulnerability occurs because teql_master_xmit() fails to update skb->dev to the slave device before transmission, causing tunnel xmit functions to reference unallocated per-CPU statistics on the TEQL master device. This allows a local or networked attacker to trigger a kernel page fault and crash the system, resulting in a denial of service. No CVSS score, EPSS risk score, or KEV active exploitation status is currently published, but patch commits are available in Linux kernel stable branches (6.18.19, 6.19.9, and 7.0-rc4).

A stack overflow vulnerability exists in the Linux kernel's tunnel transmission functions (iptunnel_xmit and ip6tunnel_xmit) due to missing recursion limits when GRE tap interfaces operate as slaves in bonded devices with broadcast mode enabled. This allows local attackers or legitimate multicast/broadcast traffic to trigger infinite recursion between bond_xmit_broadcast() and tunnel transmission functions, causing kernel stack exhaustion and denial of service. The vulnerability affects multiple Linux kernel versions and has been resolved with the addition of IP_TUNNEL_RECURSION_LIMIT (4) to prevent excessive stack consumption during nested tunnel packet encapsulation.