CVE & CISA-KEV Catalog

CVE-2015-4000

LOWEPSS 100th pctl
3.7
CVSS v3
NVD

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.

CWE-310Cryptographic IssuesCWE-295Improper Certificate Validation

How to fix

Remediation Available
nssDebian
Fixed in:2:3.19.1-1CVE-2015-4000
Fixed in:2:3.19.1-1CVE-2015-4000
Fixed in:2:3.19.1-1CVE-2015-4000
Fixed in:2:3.19.1-1CVE-2015-4000
firefoxUbuntu
Fixed in:39.0+build5-0ubuntu0.14.04.1USN-2656-1
icedtea-7-jre-jamvmUbuntu
Fixed in:7u79-2.5.6-0ubuntu1.14.04.1USN-2696-1
openjdk-7Ubuntu
Fixed in:7u79-2.5.6-0ubuntu1.14.04.1USN-2696-1
Fixed in:7u79-2.5.6-0ubuntu1.14.04.12696-1
openjdk-7-jdkUbuntu
Fixed in:7u79-2.5.6-0ubuntu1.14.04.1USN-2696-1
openjdk-7-jreUbuntu
Fixed in:7u79-2.5.6-0ubuntu1.14.04.1USN-2696-1
openjdk-7-jre-headlessUbuntu
Fixed in:7u79-2.5.6-0ubuntu1.14.04.1USN-2696-1
openjdk-7-jre-libUbuntu
Fixed in:7u79-2.5.6-0ubuntu1.14.04.1USN-2696-1
openjdk-7-jre-zeroUbuntu
Fixed in:7u79-2.5.6-0ubuntu1.14.04.1USN-2696-1
thunderbirdUbuntu
Fixed in:1:31.8.0+build1-0ubuntu0.14.04.1USN-2673-1

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Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityHigh
Privileges RequiredNone
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityNone
IntegrityLow
AvailabilityNone

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

Exploit Intelligence

99.86%probability of exploitation in 30 days
100thpercentile

Very high risk: more likely to be exploited than 100% of all known CVEs.

References

Third-Party Advisory50

Related Vulnerabilities

Other CWE-310 (Cryptographic Issues) vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2014-3566Low3.4100%-Fix
CVE-2015-0204Medium4.399%-Fix
CVE-2016-2107Medium5.989%-Fix
CVE-2016-0800Medium5.982%-Fix
CVE-2014-8684Critical9.872%--
CVE-2013-4787High9.359%--

Common questions

How do I fix CVE-2015-4000?

Published advisories record a fix for 10 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.

Is CVE-2015-4000 being actively exploited?

Not that we know of. CVE-2015-4000 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 99.9% is the estimated probability that it will be exploited in the next 30 days. That is higher than 100% of all scored CVEs.

How severe is CVE-2015-4000?

CVE-2015-4000 has a CVSS v3 base score of 3.7, rated low. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2015-4000 affect?

Published advisories record a fix for nss (Debian), firefox (Ubuntu), icedtea-7-jre-jamvm (Ubuntu), openjdk-7 (Ubuntu), and 6 more. Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-27.