CVE-2015-2320

CRITICALEPSS 89th pctl

9.8

CVSS v3

Description

The TLS stack in Mono before 3.12.1 allows remote attackers to have unspecified impact via vectors related to client-side SSLv2 fallback.

CWE-295Improper Certificate Validation

How to fix

Remediation Available

monoDebian

Fixed in:3.2.8+dfsg-10CVE-2015-2320

libmono-2.0-1Ubuntu

Fixed in:3.2.8+dfsg-4ubuntu1.1USN-2547-1

This Ubuntu release reached end-of-life on 2019-04-02.

monoUbuntu

Fixed in:3.2.8+dfsg-4ubuntu1.1USN-2547-1

This Ubuntu release reached end-of-life on 2019-04-02.

mono-runtimeUbuntu

Fixed in:3.2.8+dfsg-4ubuntu1.1USN-2547-1

This Ubuntu release reached end-of-life on 2019-04-02.

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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 ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

3.54%probability of exploitation in 30 days

89thpercentile

Elevated risk: more likely to be exploited than 89% of all known CVEs.

References

Vendor Advisory1

mono-project.com

Third-Party Advisory6

Related Vulnerabilities

Other CWE-295 (Improper Certificate Validation) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2015-4000	Low	3.7	100%	-	Fix
CVE-2020-0601	High	8.1	89%	KEV	Fix
CVE-2009-3555	Critical	9.8	87%	-	Fix
CVE-2022-26923	High	8.8	84%	KEV	Fix
CVE-2023-27823	Critical	9.8	54%	-	-
CVE-2022-42979	High	8.8	24%	-	-

Common questions

How do I fix CVE-2015-2320?

Published advisories record a fix for 4 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-2015-2320 being actively exploited?

Not that we know of. CVE-2015-2320 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 3.5% is the estimated probability that it will be exploited in the next 30 days. That is higher than 89% of all scored CVEs.

How severe is CVE-2015-2320?

CVE-2015-2320 has a CVSS v3 base score of 9.8, rated critical. 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-2015-2320 affect?

Published advisories record a fix for mono (Debian), libmono-2.0-1 (Ubuntu), mono (Ubuntu), mono-runtime (Ubuntu). 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 2026-06-17.