CVE-2015-4000

CVE-2015-4000 is a low-severity vulnerability in Openssl with a CVSS 3.x base score of 3.7. Its EPSS exploit-prediction score of 100% places it in the 100th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-310.

Key facts

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.

Frequently asked questions

What is CVE-2015-4000?
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.
How severe is CVE-2015-4000?
CVE-2015-4000 has a CVSS 3.x base score of 3.7, rated low severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2015-4000 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 100% (100th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2015-4000?
CVE-2015-4000 primarily affects Openssl. In total, 40 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2015-4000?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2015-4000 published?
CVE-2015-4000 was published on 2015-05-21 and last updated on 2026-06-17.

References

Affected products (40)

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Threat intelligence

Threat-intel indicators referencing this CVE: