CVE-2026-63626 — Mongoose: ppp_handle_ipv6cp() uses attacker-controlled length without bounds check — OOB read and heap overflow (PPP/PPPoE, MG_ENABLE_IPV6)
Mongoose is an embedded web server and network library. Prior to 7.23, ppp_handle_ipv6cp() in src/l2_ppp.c trusts the 16-bit IPv6CP len field without checking it against the rec…
Published: 2026-10-14 · CVSS: 8.8 · CVSS 3.1
Mongoose is an embedded web server and network library. Prior to 7.23, ppp_handle_ipv6cp() in src/l2_ppp.c trusts the 16-bit IPv6CP len field without checking it against the received payload size. On a PPP or PPPoE link using MG_ENABLE_TCPIP and MG_ENABLE_IPV6, an unauthenticated adjacent peer can complete the required LCP exchange and send a short Configure-Request with an oversized length, causing ppp_tx_frame() to read beyond recv_queue.buf and write beyond tx.buf. The same length misuse can also expose adjacent heap bytes in a reply or hang the event loop through find_opt(). This issue is fixed in version 7.23.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7