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Public proof of conceptFix available

CVE-2021-3449

A public proof of concept exists; no exploitation attested.

  • Published2021-03-25
  • Fixed in15.14.0 · 14.16.1 · 14.14.1 · 12.22.1 · 12.12.1 · 10.24.1
  • WeaknessCWE-476

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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).

Timeline

dates in UTC
  1. 2021-03-2515:15CVE publishedNVD
  2. 2026-10-2319:23First public proof of conceptPoC-in-GitHub
  3. 2026-10-2319:23EPSS crossed 10 %FIRST EPSS

Observed activity

isMalicious corpus · updated 2026-11-03 15:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-3449?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-3449?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV
Node.js
BranchAffectedFixed in
15.x≥ 15.0.0, < 15.14.015.14.0
14.x≥ 14.15.0, < 14.16.114.16.1
14.x≥ 14.0.0, < 14.14.114.14.1
12.x≥ 12.13.0, < 12.22.112.22.1
12.x≥ 12.0.0, < 12.12.112.12.1
10.x≥ 10.13.0, < 10.24.110.24.1
10.x≥ 10.0.0, < 10.12.110.12.1
10.x≥ 10.0.0, ≤ 10.12.0no fix published
10.x≥ 10.13.0, ≤ 10.24.0no fix published
12.x≥ 12.0.0, ≤ 12.12.0no fix published
14.x≥ 14.0.0, ≤ 14.14.0no fix published
Tenable nessus network monitor
BranchAffectedFixed in
5.11= 5.11.0no fix published
5.11= 5.11.1no fix published
5.12= 5.12.0no fix published
5.12= 5.12.1no fix published
5.13= 5.13.0no fix published
Oracle primavera unifier
BranchAffectedFixed in
17.x≥ 17.7, ≤ 17.12no fix published
19.12= 19.12no fix published
20.12= 20.12no fix published
21.12= 21.12no fix published

104 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • jbcs-httpd24-httpdRed Hat:jboss_core_services:1::el7all versions · fixed in 0:2.4.37-70.jbcs.el7and 7 other packages
  • jbcs-httpd24-mod_cluster-nativeRed Hat:jboss_core_services:1::el7all versions · fixed in 0:1.3.14-20.Final_redhat_2.jbcs.el7and 1 other package
  • jbcs-httpd24-mod_http2Red Hat:jboss_core_services:1::el7all versions · fixed in 0:1.15.7-14.jbcs.el7and 1 other package
  • jbcs-httpd24-mod_jkRed Hat:jboss_core_services:1::el7all versions · fixed in 0:1.2.48-13.redhat_1.jbcs.el7and 3 other packages
  • jbcs-httpd24-mod_mdRed Hat:jboss_core_services:1::el7all versions · fixed in 1:2.0.8-33.jbcs.el7and 1 other package
  • jbcs-httpd24-mod_securityRed Hat:jboss_core_services:1::el7all versions · fixed in 0:2.9.2-60.GA.jbcs.el7and 1 other package
  • jbcs-httpd24-mod_sslRed Hat:jboss_core_services:1::el7all versions · fixed in 1:2.4.37-70.jbcs.el7and 1 other package
  • jbcs-httpd24-nghttp2Red Hat:jboss_core_services:1::el7all versions · fixed in 0:1.39.2-37.jbcs.el7and 2 other packages

94 more package ranges on OSV.dev

Vendor advisories

  • ICSA-22-104-05 CISA95 known affected

    Siemens OpenSSL Vulnerabilities in Industrial Products

    RUGGEDCOM CROSSBOW Station Access Controller (SAC) · RUGGEDCOM RM1224 LTE(4G) EU (6GK6108-4AM00-2BA2) · RUGGEDCOM RM1224 LTE(4G) NAM (6GK6108-4AM00-2DA2) · +92 more

Full record on NVD

Fix

  1. Update Node.js to 15.14.0 · 14.16.1 · 14.14.1 · 12.22.1 · 12.12.1 · 10.24.1 · 10.12.1
  2. Vendor fix CISA ICSA-22-104-05 · 5 productsUpdate to V2.2.28 or later version
  3. Vendor fix CISA ICSA-22-104-05 · 1 productUpdate to V3.1 or later version
  4. Vendor fix CISA ICSA-22-104-05 · 1 productUpdate to V7.5 or later version
  5. Vendor fix CISA ICSA-22-104-05 · 3 productsUpdate to V17.0 Upd 2 or later version
  6. Vendor fix CISA ICSA-22-104-05 · 1 productUpdate to V1.0 SP2
  7. Mitigation from the vendor CISA ICSA-22-104-05 · 1 productRestrict access to Remote Access service, if used, to mitigate this issue. This service is disabled by default.

Advisories and patches

Detection

read 2026-11-02 22:42 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
1 repository, unverifiedriptl/cve-2021-3449
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2021-03-25
Last Modified
2026-10-08
NVD status
Modified
GitHub Advisory
GHSA-83mx-573x-5rw9

Frequently asked questions

What is CVE-2021-3449?

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).

Is CVE-2021-3449 actively exploited?

Active exploitation of CVE-2021-3449 has not been confirmed. Its EPSS score was 63.5% on 2026-11-03, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-3449?

CVE-2021-3449 has a CVSS v3 base score of 5.9 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.

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Sources for this record