CVE-2017-3733
Encrypt-Then-Mac renegotiation crash
CVE-2017-3733 is a high vulnerability (CVSS 7.5) in Openssl, published May 4, 2017. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 12.9%, the 96th percentile. Fixed in openssl 1.1.0e-1.
During a renegotiation handshake if the Encrypt-Then-Mac extension is negotiated where it was not in the original handshake (or vice-versa) then this can cause OpenSSL 1.1.0 before 1.1.0e to crash (dependent on ciphersuite). Both clients and servers are affected.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
7.5
During a renegotiation handshake if the Encrypt-Then-Mac extension is negotiated where it was not in the original handshake (or vice-versa) then this can cause OpenSSL 1.1.0 before 1.1.0e to crash (dependent on ciphersuite). Both clients and servers are affected.
- Record
CVE-2017-3733- CVSS 3.0
- 7.5 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:N/I:N/A:P - Weakness
- CWE-20
- Updated
- 2026-11-02
CVE List No score
Encrypt-Then-Mac renegotiation crash
During a renegotiation handshake if the Encrypt-Then-Mac extension is negotiated where it was not in the original handshake (or vice-versa) then this can cause OpenSSL 1.1.0 before 1.1.0e to crash (dependent on ciphersuite). Both clients and servers are affected.
- Record
CVE-2017-3733- Updated
- 2026-11-02
EUVDEUVD-2017-12850 No score
During a renegotiation handshake if the Encrypt-Then-Mac extension is negotiated where it was not in the original handshake (or vice-versa) then this can cause OpenSSL 1.1.0 before 1.1.0e to crash (dependent on ciphersuite). Both clients and servers are affected.
- Record
EUVD-2017-12850- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-6553-6v42-5wqc
7.5
During a renegotiation handshake if the Encrypt-Then-Mac extension is negotiated where it was not...
During a renegotiation handshake if the Encrypt-Then-Mac extension is negotiated where it was not in the original handshake (or vice-versa) then this can cause OpenSSL 1.1.0 before 1.1.0e to crash (dependent on ciphersuite). Both clients and servers are affected.
- Record
GHSA-6553-6v42-5wqc- CVSS 3.0
- 7.5 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-20
- Updated
- 2026-11-02
OSV
7.5
During a renegotiation handshake if the Encrypt-Then-Mac extension is negotiated where it was not in the original handshake (or vice-versa) then this can cause OpenSSL 1.1.0 before 1.1.0e to crash (dependent on ciphersuite). Both clients and servers are affected.
- Record
CVE-2017-3733- CVSS 3.0
- 7.5 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVDEBIAN-CVE-2017-3733
7.5
During a renegotiation handshake if the Encrypt-Then-Mac extension is negotiated where it was not in the original handshake (or vice-versa) then this can cause OpenSSL 1.1.0 before 1.1.0e to crash (dependent on ciphersuite). Both clients and servers are affected.
- Record
DEBIAN-CVE-2017-3733- CVSS 3.0
- 7.5 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2017-3733
7.5
During a renegotiation handshake if the Encrypt-Then-Mac extension is negotiated where it was not in the original handshake (or vice-versa) then this can cause OpenSSL 1.1.0 before 1.1.0e to crash (dependent on ciphersuite). Both clients and servers are affected.
- Record
UBUNTU-CVE-2017-3733- CVSS 3.0
- 7.5 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVMGASA-2017-0390 No score
Updated virtualbox packages fix security vulnerabilities
This update provides the virtualbox 5.1.30 maintenance release, fixing security and other issues:
In OpenSSL 1.1.0 before 1.1.0d, if a malicious server supplies bad parameters for a DHE or ECDHE key exchange then this can result in the client attempting to dereference a NULL pointer leading to a client crash. This could be exploited in a Denial of Service attack (CVE-2017-3730).
OpenSSL is vulnerable to a denial of service, caused by an out-of-bounds read when using a specific cipher. By sending specially crafted truncated packets, a remote attacker could exploit this vulnerability using CHACHA20/POLY1305 to cause the application to crash (CVE-2017-3731).
OpenSSL could allow a remote attacker to obtain sensitive information, caused by a propagation error in the BN_mod_exp() function. An attacker could exploit this vulnerability to obtain information about the private key (CVE-2017-3732).
During a renegotiation handshake if the Encrypt-Then-Mac extension is negotiated where it was not in the original handshake (or vice-versa) then this can cause OpenSSL 1.1.0 before 1.1.0e to crash (dependent on ciphersuite). Both clients and servers are affected (CVE-2017-3733)
A local user can exploit a flaw in the Oracle VM VirtualBox Core component to partially access data, partially modify data, and deny service (CVE-2017-10392, CVE-2017-10407, CVE-2017-10408).
A local user can exploit a flaw in the Oracle VM VirtualBox Core component to partially access data, partially modify data, and partially deny service (CVE-2017-10428).
For other fixes in this update see the referenced changelog.
- Record
MGASA-2017-0390- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
opensslDebian:12 |
before 1.1.0e-1 | 1.1.0e-1 |
opensslDebian:13 |
before 1.1.0e-1 | 1.1.0e-1 |
opensslDebian:14 |
before 1.1.0e-1 | 1.1.0e-1 |
virtualboxMageia:5 |
before 5.1.30-1.mga5 | 5.1.30-1.mga5 |
kmod-vboxadditionsMageia:5 |
before 5.1.30-1.mga5 | 5.1.30-1.mga5 |
kmod-virtualboxMageia:5 |
before 5.1.30-1.mga5 | 5.1.30-1.mga5 |
virtualboxMageia:6 |
before 5.1.30-1.mga6 | 5.1.30-1.mga6 |
kmod-vboxadditionsMageia:6 |
before 5.1.30-1.mga6 | 5.1.30-1.mga6 |
kmod-virtualboxMageia:6 |
before 5.1.30-1.mga6 | 5.1.30-1.mga6 |
History
| When | Changed | Sources |
|---|---|---|
| 2026-11-03 | affected | |
| 2026-11-03 | aliases | EUVD |
| 2026-11-02 | created | CVE List, GitHub Advisories, NVD, OSV |
References
securityfocus.com/bid/96269
openssl.org/news/secadv/20170216.txt
oracle.com/technetwork/security-advisory/cpujan2018-3236628.html
h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbgn03728en_us
oracle.com/technetwork/security-advisory/cpuoct2017-3236626.html
github.com/openssl/openssl/commit/4ad93618d26a3ea23d36ad5498ff4f59eff3a4d2
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securitytracker.com/id/1037846
oracle.com/technetwork/security-advisory/cpuapr2019-5072813.html
nvd.nist.gov/vuln/detail/CVE-2017-3733
github.com/advisories/GHSA-6553-6v42-5wqc
security-tracker.debian.org/tracker/CVE-2017-3733
advisories.mageia.org/MGASA-2017-0390.html
bugs.mageia.org/show_bug.cgi?id=21901
virtualbox.org/wiki/Changelog-5.1
ubuntu.com/security/CVE-2017-3733
cve.org/CVERecord?id=CVE-2017-3733