# CVE-2015-4000: Security feature bypass in n/a

> Man-in-the-middle attackers can downgrade TLS connections to weak export-grade ciphers, bypassing encryption security features.

- **Severity:** Low 3.7 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 21 May 2015
- **Updated:** 27 May 2026
- **Also known as:** CVE-2015-2723, DEBIAN-CVE-2015-4000, DLA-507-1, GHSA-v98w-p8f7-9qqf, MGASA-2015-0260, RHSA-2015:1072, SUSE-SU-2015:1482-1, SUSE-SU-2015:1526-1, SUSE-SU-2016:0344-1, SUSE-SU-2016:1618-1, SUSE-SU-2016:2209-1, SUSE-SU-2016:2385-1, SUSE-SU-2018:1768-1, SUSE-SU-2023:0586-1, UBUNTU-CVE-2015-4000, USN-2624-1

## What is CVE-2015-4000?

CVE-2015-4000 is a low-severity vulnerability in Apple Iphone Os, published on 21 May 2015. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The TLS protocol 1.2 and earlier, when a DHE_EXPORT ciphersuite is enabled on a server but not on a client, does not properly convey a DHE_EXPORT choice, which allows man-in-the-middle attackers to conduct cipher-downgrade attacks by rewriting a ClientHello with DHE replaced by DHE_EXPORT and then rewriting a ServerHello with DHE_EXPORT replaced by DHE, aka the "Logjam" issue.

Weakness: CWE-310, CWE-295 (Improper Certificate Validation)

## Which versions are affected by CVE-2015-4000?

It affects 25 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `openssl` | Red Hat:enterprise_linux:6::client | All versions | 0:1.0.1e-30.el6_6.9 |
| `openssl-debuginfo` | Red Hat:enterprise_linux:6::client | All versions | 0:1.0.1e-30.el6_6.9 |
| `openssl-devel` | Red Hat:enterprise_linux:6::client | All versions | 0:1.0.1e-30.el6_6.9 |
| `openssl-perl` | Red Hat:enterprise_linux:6::client | All versions | 0:1.0.1e-30.el6_6.9 |
| `openssl-static` | Red Hat:enterprise_linux:6::client | All versions | 0:1.0.1e-30.el6_6.9 |
| `openssl` | Red Hat:enterprise_linux:6::computenode | All versions | 0:1.0.1e-30.el6_6.9 |
| `openssl-debuginfo` | Red Hat:enterprise_linux:6::computenode | All versions | 0:1.0.1e-30.el6_6.9 |
| `openssl-devel` | Red Hat:enterprise_linux:6::computenode | All versions | 0:1.0.1e-30.el6_6.9 |
| `openssl-perl` | Red Hat:enterprise_linux:6::computenode | All versions | 0:1.0.1e-30.el6_6.9 |
| `openssl-static` | Red Hat:enterprise_linux:6::computenode | All versions | 0:1.0.1e-30.el6_6.9 |
| `openssl` | Red Hat:enterprise_linux:6::server | All versions | 0:1.0.1e-30.el6_6.9 |
| `openssl-debuginfo` | Red Hat:enterprise_linux:6::server | All versions | 0:1.0.1e-30.el6_6.9 |
| `openssl-devel` | Red Hat:enterprise_linux:6::server | All versions | 0:1.0.1e-30.el6_6.9 |
| `openssl-perl` | Red Hat:enterprise_linux:6::server | All versions | 0:1.0.1e-30.el6_6.9 |
| `openssl-static` | Red Hat:enterprise_linux:6::server | All versions | 0:1.0.1e-30.el6_6.9 |
| `openssl` | Red Hat:enterprise_linux:6::workstation | All versions | 0:1.0.1e-30.el6_6.9 |
| `openssl-debuginfo` | Red Hat:enterprise_linux:6::workstation | All versions | 0:1.0.1e-30.el6_6.9 |
| `openssl-devel` | Red Hat:enterprise_linux:6::workstation | All versions | 0:1.0.1e-30.el6_6.9 |
| `openssl-perl` | Red Hat:enterprise_linux:6::workstation | All versions | 0:1.0.1e-30.el6_6.9 |
| `openssl-static` | Red Hat:enterprise_linux:6::workstation | All versions | 0:1.0.1e-30.el6_6.9 |
| `openssl` | Red Hat:enterprise_linux:7::client | All versions | 1:1.0.1e-42.el7_1.6 |
| `openssl-debuginfo` | Red Hat:enterprise_linux:7::client | All versions | 1:1.0.1e-42.el7_1.6 |
| `openssl-devel` | Red Hat:enterprise_linux:7::client | All versions | 1:1.0.1e-42.el7_1.6 |
| `openssl-libs` | Red Hat:enterprise_linux:7::client | All versions | 1:1.0.1e-42.el7_1.6 |
| `openssl-perl` | Red Hat:enterprise_linux:7::client | All versions | 1:1.0.1e-42.el7_1.6 |
| `openssl-static` | Red Hat:enterprise_linux:7::client | All versions | 1:1.0.1e-42.el7_1.6 |
| `openssl` | Red Hat:enterprise_linux:7::computenode | All versions | 1:1.0.1e-42.el7_1.6 |
| `openssl-debuginfo` | Red Hat:enterprise_linux:7::computenode | All versions | 1:1.0.1e-42.el7_1.6 |
| `openssl-devel` | Red Hat:enterprise_linux:7::computenode | All versions | 1:1.0.1e-42.el7_1.6 |
| `openssl-libs` | Red Hat:enterprise_linux:7::computenode | All versions | 1:1.0.1e-42.el7_1.6 |
| `openssl-perl` | Red Hat:enterprise_linux:7::computenode | All versions | 1:1.0.1e-42.el7_1.6 |
| `openssl-static` | Red Hat:enterprise_linux:7::computenode | All versions | 1:1.0.1e-42.el7_1.6 |
| `openssl` | Red Hat:enterprise_linux:7::server | All versions | 1:1.0.1e-42.ael7b_1.6 |
| `openssl-debuginfo` | Red Hat:enterprise_linux:7::server | All versions | 1:1.0.1e-42.ael7b_1.6 |
| `openssl-devel` | Red Hat:enterprise_linux:7::server | All versions | 1:1.0.1e-42.ael7b_1.6 |
| `openssl-libs` | Red Hat:enterprise_linux:7::server | All versions | 1:1.0.1e-42.ael7b_1.6 |
| `openssl-perl` | Red Hat:enterprise_linux:7::server | All versions | 1:1.0.1e-42.ael7b_1.6 |
| `openssl-static` | Red Hat:enterprise_linux:7::server | All versions | 1:1.0.1e-42.ael7b_1.6 |
| `openssl` | Red Hat:enterprise_linux:7::workstation | All versions | 1:1.0.1e-42.el7_1.6 |
| `openssl-debuginfo` | Red Hat:enterprise_linux:7::workstation | All versions | 1:1.0.1e-42.el7_1.6 |

Products: Apple Iphone Os, Apple Mac Os X, Apple Safari, Canonical Ubuntu Linux, Debian Debian Linux, Google Chrome, Hp Hp-Ux, Ibm Content Manager, Microsoft Internet Explorer, Mozilla Firefox, Mozilla Firefox Esr, Mozilla Firefox Os, Mozilla Network Security Services, Mozilla Seamonkey, Mozilla Thunderbird, Openssl Openssl, Opera Opera Browser, Oracle Jdk, Oracle Jre, Oracle Jrockit and 5 more.

## How do I fix CVE-2015-4000?

Apply the vendor's patch.

## Is CVE-2015-4000 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2015-4000 exists.

Public exploit code:

- ✨ HAProxy ve Keepalived konusunu load balancer ve cluster'a ek olarak güvenlik(zayıf SSL/Kripto Kullanımı (LOGJAM) (CVE-2015-4000) zafiyeti önlemi) ve yüksek yüklere karşı ele alır. (github_poc): https://github.com/fatlan/HAProxy-Keepalived-Sec-HighLoads
- SSL/TLS Version Detection (metasploit)

## Other vulnerabilities in Apple Iphone Os

- [CVE-2021-30666](https://insights.sbomify.com/CVE-2021-30666/): Apple iOS WebKit Buffer Overflow (high 8.8, exploited in the wild)
- [CVE-2021-30761](https://insights.sbomify.com/CVE-2021-30761/): Apple iOS WebKit Memory Corruption (high 8.8, exploited in the wild)
- [CVE-2021-30762](https://insights.sbomify.com/CVE-2021-30762/): Apple iOS WebKit Use-After-Free (high 8.8, exploited in the wild)
- [CVE-2016-4657](https://insights.sbomify.com/CVE-2016-4657/): Apple iOS Webkit Memory Corruption (high 8.8, exploited in the wild)
- [CVE-2019-7286](https://insights.sbomify.com/CVE-2019-7286/): Apple Multiple Products Memory Corruption (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2015-4000 and fix it if it is affected.

What it is: CVE-2015-4000 is a low-severity vulnerability in Apple Iphone Os, published on 21 May 2015. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2015-4000 exists.

Affected product: Apple Iphone Os. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2015-4000/ (Markdown: https://insights.sbomify.com/CVE-2015-4000/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2015-4000
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2015-4000
- OSV: https://osv.dev/vulnerability/CVE-2015-4000

---
From sbomify Insights: https://insights.sbomify.com/CVE-2015-4000/
Summaries are generated and may contain mistakes; the official description above is the record.