CVE-2026-53006 in Linux
Summary
by MITRE • 06/24/2026
In the Linux kernel, the following vulnerability has been resolved:
ipv6: fix possible UAF in icmpv6_rcv()
Caching saddr and daddr before pskb_pull() is problematic since skb->head can change.
Remove these temporary variables:
- We only access &ipv6_hdr(skb)->saddr and &ipv6_hdr(skb)->daddr when net_dbg_ratelimited() is called in the slow path.
- Avoid potential future misuse after pskb_pull() call.
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Analysis
by VulDB Data Team • 06/27/2026
This vulnerability represents a use-after-free condition that can occur within the Linux kernel's IPv6 implementation, specifically in the icmpv6_rcv function. The issue arises from improper handling of socket buffer pointers during packet processing, creating a scenario where cached address information becomes invalid after memory operations. The root cause stems from caching the source and destination addresses before calling pskb_pull(), a function that can modify the underlying packet buffer structure. When skb->head changes due to this operation, previously cached pointers to ipv6_hdr(skb)->saddr and ipv6_hdr(skb)->daddr become stale references pointing to deallocated memory regions. This type of vulnerability falls under CWE-416, representing use-after-free conditions that can lead to arbitrary code execution or system instability.
The operational impact of this vulnerability is significant as it affects the fundamental networking stack of Linux systems, potentially allowing attackers to exploit memory corruption during ICMPv6 packet processing. The vulnerability manifests specifically in the slow path of packet handling where net_dbg_ratelimited() is invoked, making it particularly dangerous as it can be triggered through normal network traffic patterns. Attackers could leverage this condition to execute malicious code with kernel privileges or cause denial of service scenarios that compromise system integrity and availability. The timing of the vulnerability exposure during packet processing means that any system handling ICMPv6 traffic could be susceptible to exploitation, affecting everything from servers to embedded devices running Linux kernels.
Mitigation strategies should focus on removing the problematic caching mechanism and ensuring that address pointers are always fetched directly from the current packet buffer state after memory operations. The fix involves eliminating temporary variables that store saddr and daddr references, instead accessing these values directly when needed within the slow path execution context. This approach aligns with secure coding practices recommended in the ATT&CK framework for kernel-level defenses, specifically targeting techniques related to memory corruption vulnerabilities. System administrators should prioritize patching affected kernels as soon as possible, while network monitoring solutions should be configured to detect unusual ICMPv6 traffic patterns that might indicate exploitation attempts. Additionally, implementing proper input validation and memory management checks within the kernel networking subsystem can help prevent similar issues in future developments, emphasizing the importance of maintaining pointer validity throughout packet processing pipelines.