HOMEVULNERABILITIESCVE-2021-3449
MEDIUM

CVE-2021-3449

CWE-476Published: March 25, 2021· Updated: Jun 17, 2026

5.9
CVSS v3.1

Official Description

An OpenSSL TLS server may crash if sent a maliciously crafted renegotiation ClientHello message from a client. If a TLSv1.2 renegotiation ClientHello omits the signature_algorithms extension (where it was present in the initial ClientHello), but includes a signature_algorithms_cert extension then a NULL pointer dereference will result, leading to a crash and a denial of service attack. A server is only vulnerable if it has TLSv1.2 and renegotiation enabled (which is the default configuration). OpenSSL TLS clients are not impacted by this issue. All OpenSSL 1.1.1 versions are affected by this issue. Users of these versions should upgrade to OpenSSL 1.1.1k. OpenSSL 1.0.2 is not impacted by this issue. Fixed in OpenSSL 1.1.1k (Affected 1.1.1-1.1.1j).

NVD Source

Technical Analysis

CVE-2021-3449 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 5.9.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityHigh
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected Vendors & Products

checkpoint6 product(s)
quantum security management firmwarequantum security managementmulti-domain management firmwaremulti-domain managementquantum security gateway firmwarequantum security gateway
Debian1 product(s)
debian linux
Fedora1 product(s)
fedora
freebsd1 product(s)
freebsd
mcafee2 product(s)
web gatewayweb gateway cloud service
netapp9 product(s)
active iq unified managercloud volumes ontap mediatore-series performance analyzeroncommand insightoncommand workflow automationontap select deploy administration utilitysantricity smi-s providersnapcenterstoragegrid
Node.js1 product(s)
node.js
OpenSSL1 product(s)
openssl
Oracle14 product(s)
communications communications policy managemententerprise manager for storage managementessbasegraalvmjd edwards enterpriseone toolsjd edwards world securitymysql connectorsmysql servermysql workbenchpeoplesoft enterprise peopletoolsprimavera unifiersecure backup+2
siemens123 product(s)
ruggedcom rcm1224 firmwareruggedcom rcm1224scalance lpe9403 firmwarescalance lpe9403scalance m-800 firmwarescalance m-800scalance s602 firmwarescalance s602scalance s612 firmwarescalance s612scalance s615 firmwarescalance s615+111
sonicwall4 product(s)
sma100 firmwaresma100capture clientsonicos
tenable4 product(s)
log correlation enginenessusnessus network monitortenable.sc
Source: NVD CPE · 189 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://cert-portal.siemens.com/productcert/pdf/ssa-772220.pdf
PATCHhttps://www.oracle.com//security-alerts/cpujul2021.html
PATCHhttps://www.oracle.com/security-alerts/cpuApr2021.html
PATCHhttps://www.oracle.com/security-alerts/cpuapr2022.html
PATCHhttps://cert-portal.siemens.com/productcert/pdf/ssa-772220.pdf
PATCHhttps://www.oracle.com//security-alerts/cpujul2021.html
PATCHhttps://www.oracle.com/security-alerts/cpuApr2021.html
PATCHhttps://www.oracle.com/security-alerts/cpuapr2022.html
ADVISORYhttp://www.openwall.com/lists/oss-security/2021/03/27/1
ADVISORYhttp://www.openwall.com/lists/oss-security/2021/03/27/2
ADVISORYhttp://www.openwall.com/lists/oss-security/2021/03/28/3
ADVISORYhttp://www.openwall.com/lists/oss-security/2021/03/28/4
ADVISORYhttps://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
ADVISORYhttps://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44845
ADVISORYhttps://kc.mcafee.com/corporate/index?page=content&id=SB10356
ADVISORYhttps://lists.debian.org/debian-lts-announce/2021/08/msg00029.html
ADVISORYhttps://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0013
ADVISORYhttps://security.FreeBSD.org/advisories/FreeBSD-SA-21:07.openssl.asc
ADVISORYhttps://security.gentoo.org/glsa/202103-03
ADVISORYhttps://security.netapp.com/advisory/ntap-20210326-0006/
ADVISORYhttps://security.netapp.com/advisory/ntap-20210513-0002/
ADVISORYhttps://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-openssl-2021-GHY28dJd
ADVISORYhttps://www.debian.org/security/2021/dsa-4875
ADVISORYhttps://www.openssl.org/news/secadv/20210325.txt
ADVISORYhttps://www.oracle.com/security-alerts/cpujul2022.html
ADVISORYhttps://www.oracle.com/security-alerts/cpuoct2021.html
ADVISORYhttps://www.tenable.com/security/tns-2021-05
ADVISORYhttps://www.tenable.com/security/tns-2021-06
ADVISORYhttps://www.tenable.com/security/tns-2021-09
ADVISORYhttps://www.tenable.com/security/tns-2021-10
ADVISORYhttp://www.openwall.com/lists/oss-security/2021/03/27/1
ADVISORYhttp://www.openwall.com/lists/oss-security/2021/03/27/2
ADVISORYhttp://www.openwall.com/lists/oss-security/2021/03/28/3
ADVISORYhttp://www.openwall.com/lists/oss-security/2021/03/28/4
ADVISORYhttps://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
ADVISORYhttps://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44845
ADVISORYhttps://kc.mcafee.com/corporate/index?page=content&id=SB10356
ADVISORYhttps://lists.debian.org/debian-lts-announce/2021/08/msg00029.html
ADVISORYhttps://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0013
ADVISORYhttps://security.FreeBSD.org/advisories/FreeBSD-SA-21:07.openssl.asc
ADVISORYhttps://security.gentoo.org/glsa/202103-03
ADVISORYhttps://security.netapp.com/advisory/ntap-20210326-0006/
ADVISORYhttps://security.netapp.com/advisory/ntap-20210513-0002/
ADVISORYhttps://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-openssl-2021-GHY28dJd
ADVISORYhttps://www.debian.org/security/2021/dsa-4875
ADVISORYhttps://www.openssl.org/news/secadv/20210325.txt
ADVISORYhttps://www.oracle.com/security-alerts/cpujul2022.html
ADVISORYhttps://www.oracle.com/security-alerts/cpuoct2021.html
ADVISORYhttps://www.tenable.com/security/tns-2021-05
ADVISORYhttps://www.tenable.com/security/tns-2021-06
ADVISORYhttps://www.tenable.com/security/tns-2021-09
ADVISORYhttps://www.tenable.com/security/tns-2021-10

All References (58)

→
http://www.openwall.com/lists/oss-security/2021/03/27/1Mailing List · Third Party Advisory
→
http://www.openwall.com/lists/oss-security/2021/03/27/2Mailing List · Third Party Advisory
→
http://www.openwall.com/lists/oss-security/2021/03/28/3Mailing List · Third Party Advisory
→
http://www.openwall.com/lists/oss-security/2021/03/28/4Mailing List · Third Party Advisory
→
https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdfThird Party Advisory
→
https://cert-portal.siemens.com/productcert/pdf/ssa-772220.pdfPatch · Third Party Advisory
→
https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=fb9fa6b51defd48157eeb207f52181f735d96148
→
https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44845Third Party Advisory
→
https://kc.mcafee.com/corporate/index?page=content&id=SB10356Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2021/08/msg00029.htmlMailing List · Third Party Advisory
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CCBFLLVQVILIVGZMBJL3IXZGKWQISYNP/
→
https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0013Third Party Advisory
→
https://security.FreeBSD.org/advisories/FreeBSD-SA-21:07.openssl.ascThird Party Advisory
→
https://security.gentoo.org/glsa/202103-03Third Party Advisory
→
https://security.netapp.com/advisory/ntap-20210326-0006/Third Party Advisory

Quick Facts

CVE IDCVE-2021-3449
CVSS Score5.9 / 10
SeverityMEDIUM
WeaknessCWE-476
CISA KEVNo
Affected12 vendor(s)
PublishedMar 25, 2021

Related CVEs (CWE-476)

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CVE-2010-2495
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CVE-2023-2840
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CVE-2023-47003
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CVE-2021-4236
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CVE-2023-31129
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Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-3449 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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