# CVE-2016-10931: RUSTSEC-2016-0001 - SSL/TLS MitM vulnerability due to insecure defaults

Source: https://junglewise.ai/threats/cve-2016-10931-improper-certificate-validation-in-openssl  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2016-11-05  
License: CC BY 4.0 with a link back

CVE-2016-10931 · Severity: low · CVSS 3 · Published 2016-11-05

SSL/TLS MitM vulnerability due to insecure defaults

Technologies: [openssl (crates.io)](https://junglewise.ai/threats/technologies/crates-io-openssl). Vendors: [crates.io](https://junglewise.ai/threats/vendors/crates-io).

## Quick answers

**Is CVE-2016-10931 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2016-10931 being exploited in the wild.

**How severe is CVE-2016-10931?** Low severity, with a CVSS score of 3, published 5 November 2016.

**Which products and versions are affected?** openssl (crates.io) SEMVER:introduced=0,fixed=0.9.0, SEMVER:introduced=0.0.0-0,fixed=0.9.0.

**Is there a fix for CVE-2016-10931?** Yes. openssl (crates.io): upgrade to 0.9.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2016-10931?** Check whether you run openssl (crates.io) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- openssl (crates.io): upgrade to 0.9.0 or later

  ```sh
  cargo update -p openssl
  ```


## Affected products

- openssl (crates.io) SEMVER:introduced=0,fixed=0.9.0, SEMVER:introduced=0.0.0-0,fixed=0.9.0

## Identifiers

- CVE-2016-10931
- GHSA-34p9-f4q3-c4r7
- RUSTSEC-2016-0001

## Related threats

- [rust-openssl heap overflow in CipherCtxRef::cipher_update_inplace](https://junglewise.ai/threats/cve-2026-45784-rust-openssl-heap-overflow-in-cipherctxref-cipher-update-inplace)
- [rust-openssl heap buffer overflow in AES key-wrap-with-padding](https://junglewise.ai/threats/cve-2026-44662-rust-openssl-heap-buffer-overflow-in-aes-key-wrap-with-padding)
- [rust-openssl undefined behavior in X509Ref::ocsp_responders](https://junglewise.ai/threats/cve-2026-42327-rust-openssl-undefined-behavior-in-x509ref-ocsp-responders)
- [rust-openssl buffer over-read in PSK and cookie callbacks](https://junglewise.ai/threats/cve-2026-41898-rust-openssl-buffer-over-read-in-psk-and-cookie-callbacks)
- [rust-openssl stack buffer overflow in MdCtxRef::digest_final](https://junglewise.ai/threats/cve-2026-41681-rust-openssl-stack-buffer-overflow-in-mdctxref-digest-final)