Security advisory
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.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2017-3737
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 12:14 UTC · Revision 1
Source evidence
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.
osv:CVE-2017-3737
Complete source record
{
"id": "9baec89160eb24e400b4ae77185a171ffa542e3b7da47ad46ebe1f7822fc1e5b",
"url": "https://osv.dev/vulnerability/CVE-2017-3737",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2017-3737",
"summary": "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.",
"evidence": "osv:CVE-2017-3737",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2017-3737",
"aliases": [
"CVE-2017-3737"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/openssl/openssl",
"type": "GIT",
"events": [
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{
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{
"fixed": "898fb884b706aaeb283de4812340bb0bde8476dc"
}
],
"database_specific": {
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{
"cpe": "cpe:2.3:a:openssl:openssl:1.0.2b:*:*:*:*:*:*:*",
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{
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{
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{
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{
"cpe": "cpe:2.3:a:openssl:openssl:1.0.2d:*:*:*:*:*:*:*",
"range": [
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{
"last_affected": "1.0.2d"
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{
"cpe": "cpe:2.3:a:openssl:openssl:1.0.2e:*:*:*:*:*:*:*",
"range": [
{
"introduced": "1.0.2e"
},
{
"last_affected": "1.0.2e"
}
],
"source": "CPE_STRING"
},
{
"cpe": "cpe:2.3:a:openssl:openssl:1.0.2f:*:*:*:*:*:*:*",
"range": [
{
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{
"last_affected": "1.0.2f"
}
],
"source": "CPE_STRING"
},
{
"cpe": "cpe:2.3:a:openssl:openssl:1.0.2g:*:*:*:*:*:*:*",
"range": [
{
"introduced": "1.0.2g"
},
{
"last_affected": "1.0.2g"
}
],
"source": "CPE_STRING"
},
{
"cpe": "cpe:2.3:a:openssl:openssl:1.0.2h:*:*:*:*:*:*:*",
"range": [
{
"introduced": "1.0.2h"
},
{
"last_affected": "1.0.2h"
}
],
"source": "CPE_STRING"
},
{
"cpe": "cpe:2.3:a:openssl:openssl:1.0.2i:*:*:*:*:*:*:*",
"range": [
{
"introduced": "1.0.2i"
},
{
"last_affected": "1.0.2i"
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],
"source": "CPE_STRING"
},
{
"cpe": "cpe:2.3:a:openssl:openssl:1.0.2j:*:*:*:*:*:*:*",
"range": [
{
"introduced": "1.0.2j"
},
{
"last_affected": "1.0.2j"
}
],
"source": "CPE_STRING"
},
{
"cpe": "cpe:2.3:a:openssl:openssl:1.0.2k:*:*:*:*:*:*:*",
"range": [
{
"introduced": "1.0.2k"
},
{
"last_affected": "1.0.2k"
}
],
"source": "CPE_STRING"
},
{
"cpe": "cpe:2.3:a:openssl:openssl:1.0.2l:*:*:*:*:*:*:*",
"range": [
{
"introduced": "1.0.2l"
},
{
"last_affected": "1.0.2l"
}
],
"source": "CPE_STRING"
},
{
"cpe": "cpe:2.3:a:openssl:openssl:1.0.2m:*:*:*:*:*:*:*",
"range": [
{
"introduced": "1.0.2m"
},
{
"last_affected": "1.0.2m"
}
],
"source": "CPE_STRING"
},
{
"range": [
{
"fixed": "898fb884b706aaeb283de4812340bb0bde8476dc"
}
],
"source": "REFERENCES_COMMIT"
}
]
}
}
],
"versions": [
"1.0.2b",
"OpenSSL_1_0_2u"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2017-3737.json",
"vanir_signatures": [
{
"id": "CVE-2017-3737-cb1c25d5",
"digest": {
"threshold": 0.9,
"line_hashes": [
"328360217562015334174612851757298380863",
"190491506472494106552516757670043108211",
"217573657763067835266201114262519364526",
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},
"source": "https://github.com/openssl/openssl/commit/898fb884b706aaeb283de4812340bb0bde8476dc",
"target": {
"file": "ssl/ssl.h"
},
"deprecated": false,
"signature_type": "Line",
"signature_version": "v1"
}
],
"vanir_signatures_modified": "2026-10-20T13:23:43Z"
}
}
],
"modified": "2026-10-20T13:23:43.248254300Z",
"provider": "osv",
"references": [
"https://cert-portal.siemens.com/productcert/pdf/ssa-179516.pdf",
"https://www.tenable.com/security/tns-2017-16",
"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://security.FreeBSD.org/advisories/FreeBSD-SA-17:12.openssl.asc",
"https://security.gentoo.org/glsa/201712-03",
"https://security.netapp.com/advisory/ntap-20171208-0001/",
"https://security.netapp.com/advisory/ntap-20180117-0002/",
"https://security.netapp.com/advisory/ntap-20180419-0002/",
"https://www.debian.org/security/2017/dsa-4065",
"https://www.digitalmunition.me/2017/12/cve-2017-3737-openssl-security-bypass-vulnerability/",
"https://www.openssl.org/news/secadv/20171207.txt",
"https://www.oracle.com/technetwork/security-advisory/cpujul2019-5072835.html",
"https://github.com/openssl/openssl/commit/898fb884b706aaeb283de4812340bb0bde8476dc"
],
"provider_metadata": {
"unresolved_ranges": [
{
"cpes": [
"cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*"
],
"vendor_product": "debian:debian_linux",
"extracted_events": [
{
"range": [
{
"introduced": "9.0"
},
{
"last_affected": "9.0"
}
],
"source": "CPE_STRING"
}
]
}
]
}
},
"related_cves": [
{
"value": "CVE-2017-3737",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 387617,
"published_at": "2017-12-07T16:29:00.193+00:00"
}