CVE-2017-7892

Publication date 17 April 2017

Last updated 25 August 2025

Ubuntu priority

Cvss 3 Severity Score

Description

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.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
capnproto	18.04 LTS bionic	Fixed 0.6.1-1
	17.10 artful	Ignored end of life
	17.04 zesty	Ignored end of life
	16.10 yakkety	Ignored end of life
	16.04 LTS xenial	Fixed 0.5.3-2ubuntu1.1
	14.04 LTS trusty	Fixed 0.4.0-1ubuntu2.1
	12.04 LTS precise	Not in release

Notes

ratliff

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

Severity score breakdown

CVSS version: CVSS v3.0

Base score 7.5 · High

Base metrics

Parameter	Value
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality impact	None
Integrity impact	None
Availability impact	High

Scores

Parameter	Value
Base score	7.5 · High
Exploitability score	-
Impact score	-

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H