CVE-2016-10931 Improper Certificate Validation in openssl
Attackers can perform man-in-the-middle attacks because the Rust OpenSSL crate disables certificate verification by default and lacks hostname verification APIs.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2016-10931?
CVE-2016-10931 is a high-severity vulnerability in n/a, published on 26 Aug 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
An issue was discovered in the openssl crate before 0.9.0 for Rust. There is an SSL/TLS man-in-the-middle vulnerability because certificate verification is off by default and there is no API for hostname verification.
Weakness: CWE-295
Which versions are affected by CVE-2016-10931?
3 open source packages ship an affected version, including openssl. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
openssl crates.io | All versions | 0.9.0 |
openssl crates.io | All versions | 0.9.0 |
openssl crates.io | From 0.0.0-0 | 0.9.0 |
Products include Rust-Openssl Project Rust-Openssl.
How do I fix CVE-2016-10931?
Upgrade openssl to 0.9.0 or later.
Is CVE-2016-10931 being exploited?
There is no known exploitation of CVE-2016-10931 in the wild and no public exploit code.
Other vulnerabilities in n/a
- CVE-2018-20997 Use after free in openssl
- CVE-2026-41898 rust-openssl: Unchecked callback length in PSK/cookie trampolines leaks adjacent memory to peer
- CVE-2026-41681 rust-openssl: MdCtxRef::digest_final() writes past caller buffer with no length check
- CVE-2026-41676 rust-openssl: Deriver::derive and PkeyCtxRef::derive can overflow short buffers on OpenSSL 1.1.1
- CVE-2026-41678 rust-openssl: Incorrect bounds assertion in aes key wrap
Sources
Also known as GHSA-34p9-f4q3-c4r7, RUSTSEC-2016-0001.