No exploitation reportedFix available

CVE-2017-3737

No exploitation reported by the sources we read.

Published2017-12-07
WeaknessCWE-125 · CWE-787

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

OpenSSL 1.0.2 (starting from version 1.0.2b) introduced an "error state" mechanism. The intent was that if a fatal error occurred during a handshake then OpenSSL would move into the error state and would immediately fail if you attempted to continue the handshake. This works as designed for the explicit handshake functions (SSL_do_handshake(), SSL_accept() and SSL_connect()), however due to a bug it does not work correctly if SSL_read() or SSL_write() is called directly. In that scenario, if the handshake fails then a fatal error will be returned in the initial function call. If SSL_read()/SSL_write() is subsequently called by the application for the same SSL object then it will succeed and the data is passed without being decrypted/encrypted directly from the SSL/TLS record layer. In order to exploit this issue an application bug would have to be present that resulted in a call to SSL_read()/SSL_write() being issued after having already received a fatal error. OpenSSL version 1.0.2b-1.0.2m are affected. Fixed in OpenSSL 1.0.2n. OpenSSL 1.1.0 is not affected.

Timeline

dates in UTC

2017-12-0716:29CVE publishedNVD
2026-10-2319:23EPSS crossed 10 %FIRST EPSS

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2017-3737?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2017-3737?format=csv
TAXII collection of exploited CVEs
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Versions per branch

NVD

OpenSSL

Branch	Affected	Fixed in	Source
1.0	= 1.0.2b	no fix published	NVD
1.0	= 1.0.2c	no fix published	NVD
1.0	= 1.0.2d	no fix published	NVD
1.0	= 1.0.2e	no fix published	NVD
1.0	= 1.0.2f	no fix published	NVD
1.0	= 1.0.2g	no fix published	NVD
1.0	= 1.0.2h	no fix published	NVD
1.0	= 1.0.2i	no fix published	NVD
1.0	= 1.0.2j	no fix published	NVD
1.0	= 1.0.2k	no fix published	NVD
1.0	= 1.0.2l	no fix published	NVD
1.0	= 1.0.2m	no fix published	NVD

Debian debian linux

Branch	Affected	Fixed in	Source
9.0	= 9.0	no fix published	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

ICSA-18-226-02 CISA20 known affected
Siemens OpenSSL Vulnerability in Industrial Products (Update E)
MindConnect IoT2040 · MindConnect Nano (IPC227D) · SIMATIC ET 200SP Open Controller CPU 1515SP PC (incl. SIPLUS variants) · +17 more

Full record on NVD

Fix

Vendor fix CISA ICSA-18-226-02 · 1 productUpdate to V3.14 P021 or later version
Vendor fix CISA ICSA-18-226-02 · 1 productUpdate to V3.15 P014 or later version
Vendor fix CISA ICSA-18-226-02 · 1 productUpdate to V3.16 P002 or later version
Vendor fix CISA ICSA-18-226-02 · 1 productUpdate to V2.0.12 / 3.0.12, installing latest Sinumerik Integrate Product suite.
Vendor fix CISA ICSA-18-226-02 · 1 productUpdate to V4.1.8, installing latest Sinumerik Integrate Product suite.
Vendor fix CISA ICSA-18-226-02 · 1 productUpdate to V2.6 or later version

Advisories and patches

www.openssl.orgVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVSS 3.05.9read 2026-10-23
NVDCVSS 2.04.3read 2026-10-23
NVDweakness (CWE)CWE-125, CWE-787read 2026-10-23
FIRST EPSSEPSS score78.7 %read 2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Published: 2017-12-07
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2017-3737?

Is CVE-2017-3737 actively exploited?

Active exploitation of CVE-2017-3737 has not been confirmed. Its EPSS score was 78.7% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2017-3737?

CVE-2017-3737 has a CVSS v3 base score of 5.9 (MEDIUM severity), with vector string CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N.

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