rcu

About this tag
The rcu tag on WindowsForum.com covers Linux kernel vulnerabilities and fixes that involve Read-Copy-Update (RCU) synchronization primitives. Discussions focus on use-after-free bugs in subsystems such as netfilter (nftables), Wi-Fi drivers (wilc1000), MD RAID, TCP Fast Open, NVMe over Fibre Channel, IPv6 transmit path, and SMC networking. Common themes include race conditions, RCU misuse, and patches that add or correct RCU read-side critical sections or use RCU-aware accessors like dst_dev_rcu. Content is aimed at system administrators and kernel developers needing to understand and apply urgent security updates.

  1. CVE-2026-23231: Linux nf_tables UAF Fix with synchronize_rcu

    The Linux kernel's netfilter subsystem has a new, high-consequence memory-corruption fix that any Linux systems team running nftables must treat as urgent: CVE-2026-23231 patches a race-triggered use-after-free in nf_tables_addchain() that can leave published chain objects accessible to active...
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    • linux kernel security nftables rcu use-after-free
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    • Forum: Security Alerts

  2. Linux Wilc1000 RCU Vulnerability CVE-2024-27053 Denial of Service

    A subtle misuse of the Linux kernel’s Read-Copy-Update (RCU) primitives in the WILC1000 Wi‑Fi driver has surfaced as CVE-2024-27053, a high‑severity flaw that can lead to sustained or persistent denial‑of‑service for affected systems and — under specific race conditions — risks more serious...

  3. CVE-2025-68374: Linux MD RAID RCU Lifetime Use-After-Free Bug

    A new Linux kernel vulnerability, tracked as CVE‑2025‑68374, corrects a subtle but serious RCU lifetime bug in the md (multiple‑device / software RAID) subsystem: maintainers attempted to use RCU to protect a pointer named thread, but passed that raw pointer into md_wakeup_thread before entering...

  4. Linux Kernel CVE-2025-68188: RCU based fix for TCP Fast Open UAF

    The Linux kernel has received a targeted, low‑risk hardening to close a race that could lead to a use‑after‑free in a TCP Fast Open helper: CVE‑2025‑68188 updates tcp_fastopen_active_disable_ofo_check to use the RCU‑aware helper dst_dev_rcu, removing a small timing window tied to atomic...

  5. Linux NVMe FC CVE-2025-40343: Fix for double deletion race in nvmet-fc

    A subtle race in the Linux kernel’s NVMe‑over‑Fibre‑Channel stack was assigned CVE‑2025‑40343 after maintainers fixed a sequencing bug that could let the same association deletion be scheduled twice during a forced port shutdown — a corner case that, in the field, risks freeing resources twice...

  6. CVE-2025-40158 IPv6 RCU Use-After-Free in Linux Kernel

    A recently disclosed Linux kernel vulnerability, tracked as CVE-2025-40158, affects the IPv6 transmit path: a race-condition/RCU misuse in the ip6_output / ip6_finish_output2 code that can lead to a possible use‑after‑free (UAF) when the kernel reads the destination device pointer; the upstream...

  7. Linux Kernel Networking Hardening for CVE-2025-40170: RCU dst_dev_rcu

    A focused, low‑risk kernel hardening landed as CVE‑2025‑40170: maintainers switched several network call paths to RCU‑aware device access (use of dst_dev_rcu to remove transient pointer races in sk_setup_caps and a handful of related functions, closing a window that could cause kernel oopses or...
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    • cve 2025 40170 linux kernel network security rcu
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    • Forum: Security Alerts

  8. Linux SMC Kernel UAF Fixed: RCU Aware Access in smc_clc_prfx_match

    The Linux kernel team fixed a subtle but potentially disruptive use‑after‑free (UAF) in the SMC networking code by changing how a socket’s destination device is obtained inside smc_clc_prfx_match: callers now use the RCU‑aware accessors __sk_dst_get and dst_dev_rcu instead of a direct...

  9. Linux Kernel TLS Path Hardened: Safe dst Access with __sk_dst_get and dst_dev_rcu

    A subtle change in the Linux kernel networking stack — switching get_netdev_for_sock to use __sk_dst_get and dst_dev_rcu — was published as CVE-2025-40149 and patches were merged upstream to remove a potential use‑after‑free (UAF) when callers accessed a transient device pointer outside an RCU...