How severe is CVE-2015-1671?

CVE-2015-1671 has a CVSS score of 7.8/10, rated HIGH. Immediate patching is strongly recommended.

Which products are affected by CVE-2015-1671?

Affected package information for CVE-2015-1671 is not yet fully mapped. Check the official advisory links for details.

How do I patch CVE-2015-1671?

No patch has shipped for CVE-2015-1671 yet — track the microsoft .net framework advisory for a fixed release and apply the workarounds below in the meantime.

How do I detect CVE-2015-1671 across my infrastructure?

Inventory every microsoft .net framework deployment and check each version against the affected-products list above. Because the exploit targets the running system rather than your application code, also watch for remote code execution at the network and runtime layer — O3 flags the exploit behaviour from runtime telemetry and egress traffic even before a vulnerable build is confirmed.

How do I mitigate CVE-2015-1671 if there is no patch (or I can't update yet)?

Cut exposure now: restrict the management/admin interface to trusted networks, segment the device, and apply the vendor's recommended configuration mitigations and any WAF/IPS signature. O3's runtime protection blocks the exploit chain at execution, holding the line on unpatched or end-of-life systems until you can patch.

How does O3 Security protect against CVE-2015-1671?

O3 detects and blocks CVE-2015-1671 exploitation at runtime: eBPF exploit-chain detection, plus L7 egress monitoring that catches the post-exploitation callback and severs the attacker's outbound channel.

Is CVE-2015-1671 actively exploited in the wild?

Yes. There are 2 known exploit references for CVE-2015-1671, including 2 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2015-1671?

CVE-2015-1671 has an EPSS (Exploit Prediction Scoring System) score of 54.6%, placing it in the 99th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

Is CVE-2015-1671 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2015-1671 (Microsoft Windows Remote Code Execution Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2022-05-25. CISA required all US federal civilian agencies to remediate this vulnerability by 2022-06-15. The required action was: Apply updates per vendor instructions. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

Which products and versions are affected by CVE-2015-1671?

CVE-2015-1671 affects microsoft .net framework (7 versions, e.g. 3.0, 3.5, 3.5.1…); microsoft live meeting (1 version, e.g. 2007); microsoft lync (2 versions, e.g. 2010, 2013); microsoft silverlight (1 version, e.g. 5.0). Check the affected-products list on this page against your deployed version to confirm exposure.

When was CVE-2015-1671 published, and has it been updated?

CVE-2015-1671 was published on May 13, 2015 and was last updated on June 17, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CISA KEV·Added 2022-05-25 — agencies required to remediate by 2022-06-15

CVE-2015-1671

HIGH

The Windows DirectWrite library, as used in Microsoft .NET Framework 3.0 SP2, 3.5, 3.5.1, 4, 4.5, 4.5.1, and 4.5.2; Office 2007 SP3 and 2010 SP2; Live Meeting 2007 Console; Lync 2010;…

Published

May 13, 2015

Updated

Jun 17, 2026

Affected

0 pkgs

Patched

None yet

Exploits

2 known

EPSS Exploitation Probability

via FIRST.org ↗

54.6%probability of exploitation in next 30 days

High Risk99th percentile0.00%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Description

The Windows DirectWrite library, as used in Microsoft .NET Framework 3.0 SP2, 3.5, 3.5.1, 4, 4.5, 4.5.1, and 4.5.2; Office 2007 SP3 and 2010 SP2; Live Meeting 2007 Console; Lync 2010; Lync 2010 Attendee; Lync 2013 SP1; Lync Basic 2013 SP1; Silverlight 5 before 5.1.40416.00; and Silverlight 5 Developer Runtime before 5.1.40416.00, allows remote attackers to execute arbitrary code via a crafted TrueType font, aka "TrueType Font Parsing Vulnerability."

Affected Products

4 products · 15 configurations

Application

.net frameworkmicrosoft

7 versions

3.03.53.5.14.04.54.5.14.5.2

Application

live meetingmicrosoft

1 version

2007

Application

lyncmicrosoft

2 versions

20102013

Application

silverlightmicrosoft

1 version

5.0

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

The Windows DirectWrite library, as used in Microsoft .NET Framework 3.0…

cisa.govCISAMay 2022

The Windows DirectWrite library, as used in Microsoft .NET Framework 3.0…

malware289.rssing.comAPIJul 2015

Detection & mitigation playbook

Vendor / appliance

Detect
Inventory every microsoft .net framework deployment and check each version against the affected-products list above. Because the exploit targets the running system rather than your application code, also watch for remote code execution at the network and runtime layer — O3 flags the exploit behaviour from runtime telemetry and egress traffic even before a vulnerable build is confirmed.
Remediation status
No patch has shipped for CVE-2015-1671 yet — track the microsoft .net framework advisory for a fixed release and apply the workarounds below in the meantime.
Mitigate without a patch
Cut exposure now: restrict the management/admin interface to trusted networks, segment the device, and apply the vendor's recommended configuration mitigations and any WAF/IPS signature. O3's runtime protection blocks the exploit chain at execution, holding the line on unpatched or end-of-life systems until you can patch.
How O3 protects you
O3 detects and blocks CVE-2015-1671 exploitation at runtime: eBPF exploit-chain detection, plus L7 egress monitoring that catches the post-exploitation callback and severs the attacker's outbound channel.

Tailored to CVE-2015-1671. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

O3 Security · Runtime Protection

Is CVE-2015-1671 being exploited in your environment?

O3's eBPF runtime sensors and L7 egress monitoring detect and block the CVE-2015-1671 exploit chain at execution — protecting unpatched and end-of-life systems until the vendor patch is applied.

Protect my workloads How runtime protection works

CVE-2015-1671

EPSS Exploitation Probability

Description

Affected Products

Detection & mitigation playbook

Detect

Remediation status

Mitigate without a patch

How O3 protects you

Frequently Asked Questions

Is CVE-2015-1671 being exploited in your environment?