CVE-2017-3737
OpenSSL 1.0.2 (starting from version 1.0.2b) introduced an "error state" mechanism.
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 78.7%, higher than 100% of all known CVEs. Patch or mitigate before the next change window.
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.
- CVSS 3.0
- 5.9 MEDIUMCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
- EPSS
- 78.67% probability · 100th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-125, CWE-787
- Affected
- openssl/openssl · debian/debian linux
- Source
- openssl-security@openssl.org
EPSS 78.7% since 27 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- 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/102103Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1039978Third 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.ascThird Party Advisory
- https://security.gentoo.org/glsa/201712-03Third 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-4065Third 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.txtVendor Advisory
- https://www.oracle.com/technetwork/security-advisory/cpujul2019-5072835.html
- https://www.tenable.com/security/tns-2017-16
- 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/102103Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1039978Third 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
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.