This CVE documents a buffer overflow in the Linux kernel’s PPP synchronised tty handling. The function ppp_sync_txmunge() prepends address and control bytes to a packet without ensuring that the socket buffer header is writable. As a result, a crafted PPP frame can overwrite data that remains visible to an AF_PACKET socket, leading to kernel memory corruption and potential loss of service.

The flaw applies to every Linux kernel that has not incorporated the fix adding skb_cow_head() in ppp_sync_txmunge(). No specific version range is listed, so systems running older kernels or unpatched distributions are potentially vulnerable.

With a CVSS score of 5.5 and an EPSS below 1%, the risk is moderate. The vulnerability is not in the CISA KEV catalog. Exploitation requires the delivery of malicious PPP frames to a bridged synchronous tty channel. An attacker who can do so may cause kernel memory corruption leading to a denial of service. No evidence of remote code execution or privilege escalation is indicated by the current description.