CVE-2017-3737

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.

Published: 2017-12-07 Last update: 2026-05-13 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2017-3737 is rated Moderate Risk (52.7/100): CVSS Medium severity, with high exploitation likelihood (EPSS 42.93%, 97th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2017-3737

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-28 57.95% 42.93% -15.02%
2 2026-03-22 42.93% 57.95% +15.02%
3 2026-03-04 — 42.93% —

Full EPSS history (61 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2017-3737

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.9 3.0 MEDIUM
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.2 3.6 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2017-3737

OS Trackers for CVE-2017-3737

vendor priority summary link
debian not yet assigned CVE-2017-3737 not yet assigned priority: Debian including 1 source packages (openssl), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2017-3737
gentoo normal CVE-2017-3737: 1 GLSA(s) (201712-03), 1 atom(s) (dev-libs/openssl); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2017-3737
redhat medium — https://access.redhat.com/security/cve/CVE-2017-3737
suse medium CVE-2017-3737 severity moderate: SUSE including 340 source package names (0.9.1:libopenssl1_0_0-1.0.2j-60.20.2, 0.9.1:openssl-1.0.2j-60.20.2, …), 572 product×package rows across 72 product lines (Container caasp/v4/default-http-backend, Container caasp/v4/dnsmasq-nanny, … (72 product lines)): Known Affected 231, Known Not Affected 184, Fixed 157. https://www.suse.com/security/cve/CVE-2017-3737/
ubuntu medium CVE-2017-3737 medium priority: Ubuntu including 1 source packages (openssl), 5 status rows across 5 suites (artful, trusty, upstream, xenial, zesty): released 3, needs-triage 1, not-affected 1. https://ubuntu.com/security/CVE-2017-3737

Affected software / configurations for CVE-2017-3737

Vendor Product Version Raw CPE
openssl openssl 1.0.2b cpe:2.3:a:openssl:openssl:1.0.2b:*:*:*:*:*:*:*
openssl openssl 1.0.2c cpe:2.3:a:openssl:openssl:1.0.2c:*:*:*:*:*:*:*
openssl openssl 1.0.2d cpe:2.3:a:openssl:openssl:1.0.2d:*:*:*:*:*:*:*
openssl openssl 1.0.2e cpe:2.3:a:openssl:openssl:1.0.2e:*:*:*:*:*:*:*
openssl openssl 1.0.2f cpe:2.3:a:openssl:openssl:1.0.2f:*:*:*:*:*:*:*
openssl openssl 1.0.2g cpe:2.3:a:openssl:openssl:1.0.2g:*:*:*:*:*:*:*
openssl openssl 1.0.2h cpe:2.3:a:openssl:openssl:1.0.2h:*:*:*:*:*:*:*
openssl openssl 1.0.2i cpe:2.3:a:openssl:openssl:1.0.2i:*:*:*:*:*:*:*
openssl openssl 1.0.2j cpe:2.3:a:openssl:openssl:1.0.2j:*:*:*:*:*:*:*
openssl openssl 1.0.2k cpe:2.3:a:openssl:openssl:1.0.2k:*:*:*:*:*:*:*
openssl openssl 1.0.2l cpe:2.3:a:openssl:openssl:1.0.2l:*:*:*:*:*:*:*
openssl openssl 1.0.2m cpe:2.3:a:openssl:openssl:1.0.2m:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*

References for CVE-2017-3737

URL Tags
http://www.oracle.com/technetwork/security-advisory/cpuapr2018-3678067.html
http://www.oracle.com/technetwork/security-advisory/cpujan2018-3236628.html
http://www.oracle.com/technetwork/security-advisory/cpujul2018-4258247.html
http://www.securityfocus.com/bid/102103 Third Party Advisory VDB Entry
http://www.securitytracker.com/id/1039978 Third Party Advisory VDB Entry
https://access.redhat.com/errata/RHSA-2018:0998
https://access.redhat.com/errata/RHSA-2018:2185
https://access.redhat.com/errata/RHSA-2018:2186
https://access.redhat.com/errata/RHSA-2018:2187
https://cert-portal.siemens.com/productcert/pdf/ssa-179516.pdf
https://github.com/openssl/openssl/commit/898fb884b706aaeb283de4812340bb0bde8476dc
https://security.FreeBSD.org/advisories/FreeBSD-SA-17:12.openssl.asc Third Party Advisory
https://security.gentoo.org/glsa/201712-03 Third Party Advisory
https://security.netapp.com/advisory/ntap-20171208-0001/ Third Party Advisory
https://security.netapp.com/advisory/ntap-20180117-0002/
https://security.netapp.com/advisory/ntap-20180419-0002/
https://www.debian.org/security/2017/dsa-4065 Third Party Advisory
https://www.digitalmunition.me/2017/12/cve-2017-3737-openssl-security-bypass-vulnerability/ Third Party Advisory
https://www.openssl.org/news/secadv/20171207.txt Vendor Advisory
https://www.oracle.com/technetwork/security-advisory/cpujul2019-5072835.html
https://www.tenable.com/security/tns-2017-16
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