---
title: "CVE-2015-7940\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2015-7940?format=md
keywords: index, follow
---

# CVE-2015-7940

Publication date 9 November 2015

Last updated 24 July 2024

---

Ubuntu priority

**Low**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

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## Description

The Bouncy Castle Java library before 1.51 does not validate a point is
withing the elliptic curve, which makes it easier for remote attackers to
obtain private keys via a series of crafted elliptic curve Diffie Hellman
(ECDH) key exchanges, aka an "invalid curve attack."

[Read the notes from the security team](https://ubuntu.com/security/CVE-2015-7940?format=md#notes)

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| bouncycastle | 18.04 LTS bionic | Not affected |
| 17.10 artful | Not affected |
| 17.04 zesty | Ignored end of life |
| 16.10 yakkety | Ignored end of life |
| 16.04 LTS xenial | Not affected |
| 15.10 wily | Ignored end of life |
| 15.04 vivid | Ignored end of life |
| 14.04 LTS trusty | Fixed 1.49+dfsg-2ubuntu0.1 |
| 12.04 LTS precise | Ignored end of life |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)
* [Patch details](https://ubuntu.com/security/CVE-2015-7940?format=md#patch-details)

## Notes

---

### [mdeslaur](https://launchpad.net/~mdeslaur)

no reverse depends in main

### Patch details

For informational purposes only. We recommend not to cherry-pick updates. [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)

| Package | Patch details |
| --- | --- |
| bouncycastle | * Upstream:   [5cb2f05](https://github.com/bcgit/bc-java/commit/5cb2f0578e6ec8f0d67e59d05d8c4704d8e05f83) * Upstream:   [e25e94a](https://github.com/bcgit/bc-java/commit/e25e94a046a6934819133886439984e2fecb2b04) |

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-7940)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2015-7940)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2015-7940)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2015-7940)

### Related Ubuntu Security Notices (USN)

+ [USN-3727-1](https://usn.ubuntu.com/USN-3727-1)
+ Bouncy Castle vulnerabilities
+ 1 August 2018

### Other references

* <https://web-in-security.blogspot.ca/2015/09/practical-invalid-curve-attacks.html>
* <https://www.cve.org/CVERecord?id=CVE-2015-7940>