Published: 17 April 2017
Sandstorm Cap'n Proto before 0.5.3.1 allows remote crashes related to a compiler optimization. A remote attacker can trigger a segfault in a 32-bit libcapnp application because Cap'n Proto relies on pointer arithmetic calculations that overflow. An example compiler with optimization that elides a bounds check in such calculations is Apple LLVM version 8.1.0 (clang-802.0.41). The attack vector is a crafted far pointer within a message.
From the Ubuntu security team
Kenton Varda discovered that the Cap'n Proto utility has a buffer overflow vulnerability. An attacker could use this vulnerability to cause a crash or possibly execute arbitrary code.
CVSS 3 base score: 7.5
Advisory: "Some bounds checks are elided by Apple's compiler and possibly others, leading to a possible attack especially in 32-bit builds." Setting status to needs-triage to investigate whether it impacts Ubuntu