In the Linux kernel, an off‑by‑one error in the 6lowpan multicast context address compression logic incorrectly copies memory, corrupting the RIID field and leaving a 4‑byte region of uninitialized kernel stack data in the compressed packet. When that packet is transmitted, the uninitialized bytes are exposed to any observer on the network, allowing an attacker to read portions of the kernel stack and potentially extract sensitive information. The vulnerability is a classic case of an off‑by‑one bug leading to information disclosure.

All Linux kernel builds prior to the application of the patch commit (06ce6fc1…) that includes the lowpan_iphc_mcast_ctx_addr_compress fix. The bug affects the 6lowpan multicast traffic is potentially impacted.

The CVSS score is not available, and the EPSS is not disclosed, but the risk can be reasoned from the description: an attacker must craft a lowpan multicast packet and observe it on the network. No public exploit is known, and the vulnerability is limited to the transmission of kernel data rather than providing full remote code execution. However, the possibility of leaking kernel stack contents can aid in further attacks and, therefore, should be addressed promptly. The bug is not listed in the CISA impact warrants a high priority response for exposed systems.