CVE-2021-3449: NULL pointer deref in signature_algorithms processing
Noroxi assessment
Priority: Plan (action score 42/100)
- Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
- Probability of exploitation in the next 30 days: 63.5% (FIRST EPSS); higher than 99.2% of all records.
- Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
- According to CISA the attack is automatable: targets can be found by mass scanning.
- Fixed version: openssl (Alpine:v3.10) 1.1.1k-r0; openssl3 (Alpine:v3.15) 1.1.1k-r0; openssl-src (crates.io) 111.15.0.
- Mentioned 6 times in Turkish national cyber security advisories (siberguvenlik.gov.tr).
Add it to your regular patch cycle. Upgrade to openssl (Alpine:v3.10) 1.1.1k-r0; openssl3 (Alpine:v3.15) 1.1.1k-r0; openssl-src (crates.io) 111.15.0 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
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).
- BDU:2021-01844
- GHSA-83mx-573x-5rw9
- DSA-4875-1
- openSUSE-SU-2021:0476-1
- openSUSE-SU-2021:1059-1
- openSUSE-SU-2021:1061-1
- openSUSE-SU-2021:2327-1
- openSUSE-SU-2021:2353-1
- openSUSE-SU-2024:11041-1
- RHSA-2021:1024
- RHSA-2021:1063
- RHSA-2021:1131
- RHSA-2021:1189
- RHSA-2021:1195
- RHSA-2021:1199
- RHSA-2021:1202
- RLSA-2021:1024
- RUSTSEC-2021-0055
- SUSE-SU-2021:0954-1
- SUSE-SU-2021:0955-1
- Published
- Mar 25, 2021
- Updated
- Oct 8, 2026
- EPSS
- 63.5% · 99th percentile
- CWE
- CWE-476
Report tools
Action score
42
Plan
Add it to your regular patch cycle.
- CVSS
- 23 / 40 · 5.9 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 19 / 30 · 63.5%
CISA SSVC decision
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- Proof of concept exists, no weaponized module
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| openssl | openssl | cpe:2.3:a:openssl:openssl |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
| freebsd | freebsd | cpe:2.3:o:freebsd:freebsd |
| netapp | active iq unified manager | cpe:2.3:a:netapp:active_iq_unified_manager |
| netapp | cloud volumes ontap mediator | cpe:2.3:a:netapp:cloud_volumes_ontap_mediator |
| netapp | e-series performance analyzer | cpe:2.3:a:netapp:e-series_performance_analyzer |
| netapp | oncommand insight | cpe:2.3:a:netapp:oncommand_insight |
| netapp | oncommand workflow automation | cpe:2.3:a:netapp:oncommand_workflow_automation |
| netapp | ontap select deploy administration utility | cpe:2.3:a:netapp:ontap_select_deploy_administration_utility |
| netapp | santricity smi-s provider | cpe:2.3:a:netapp:santricity_smi-s_provider |
| netapp | snapcenter | cpe:2.3:a:netapp:snapcenter |
| netapp | storagegrid | cpe:2.3:a:netapp:storagegrid |
and 155 more
Check your server's TLS configuration
The OpenSSL version can't be seen from outside; the free SSL checker tests your certificate, enabled TLS versions and weak ciphers. Confirm the version on your server with the package manager.
Run the SSL checkAffected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- checkpoint multi-domain management firmwarer80.40
- checkpoint multi-domain management firmwarer81
- checkpoint quantum security gateway firmwarer80.40
- checkpoint quantum security gateway firmwarer81
- checkpoint quantum security management firmwarer80.40
- checkpoint quantum security management firmwarer81
- debian debian linux10.0
- debian debian linux9.0
- fedoraproject fedora34
- freebsd freebsd12.2
- mcafee web gateway10.1.1
- mcafee web gateway8.2.19
- mcafee web gateway9.2.10
- mcafee web gateway cloud service10.1.1
- mcafee web gateway cloud service8.2.19
- mcafee web gateway cloud service9.2.10
- netapp active iq unified managerall versions
- netapp cloud volumes ontap mediatorall versions
- netapp e-series performance analyzerall versions
- netapp oncommand insightall versions
Versions reported by the vendor
Affected version ranges reported by the assigning authority (openssl). Independent of NVD's CPE analysis and usually ahead of it.
OpenSSL OpenSSL
- Fixed in OpenSSL 1.1.1k (Affected 1.1.1-1.1.1j)affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Alpine:v3.10 | openssl | from 1.1.1 · before 1.1.1k-r0 | 1.1.1k-r0 |
| Alpine:v3.15 | openssl3 | before 1.1.1k-r0 | 1.1.1k-r0 |
| crates.io | openssl-src | from 0.0.0-0 · before 111.15.0 | 111.15.0 |
| crates.io | openssl-src | before 111.15.0 | 111.15.0 |
| Debian:10 | openssl | before 1.1.1d-0+deb10u6 | 1.1.1d-0+deb10u6 |
| Debian:12 | openssl | before 1.1.1k-1 | 1.1.1k-1 |
| openSUSE:Leap 15.2 | nodejs10 | before 10.24.1-lp152.2.15.1 | 10.24.1-lp152.2.15.1 |
| openSUSE:Leap 15.2 | nodejs12 | before 12.22.2-lp152.3.15.1 | 12.22.2-lp152.3.15.1 |
| openSUSE:Leap 15.2 | openssl-1_1 | before 1.1.1d-lp152.7.15.1 | 1.1.1d-lp152.7.15.1 |
| openSUSE:Leap 15.3 | nodejs10 | before 10.24.1-1.36.1 | 10.24.1-1.36.1 |
| openSUSE:Leap 15.3 | nodejs12 | before 12.22.2-4.16.1 | 12.22.2-4.16.1 |
| openSUSE:Tumbleweed | matrix-synapse | before 1.43.0-1.1 | 1.43.0-1.1 |
| Red Hat:enterprise_linux:8::baseos | openssl | before 1:1.1.1g-15.el8_3 | 1:1.1.1g-15.el8_3 |
| Red Hat:enterprise_linux:8::baseos | openssl-debuginfo | before 1:1.1.1g-15.el8_3 | 1:1.1.1g-15.el8_3 |
| Red Hat:enterprise_linux:8::baseos | openssl-debugsource | before 1:1.1.1g-15.el8_3 | 1:1.1.1g-15.el8_3 |
| Red Hat:enterprise_linux:8::baseos | openssl-devel | before 1:1.1.1g-15.el8_3 | 1:1.1.1g-15.el8_3 |
| Red Hat:enterprise_linux:8::baseos | openssl-libs | before 1:1.1.1g-15.el8_3 | 1:1.1.1g-15.el8_3 |
| Red Hat:enterprise_linux:8::baseos | openssl-libs-debuginfo | before 1:1.1.1g-15.el8_3 | 1:1.1.1g-15.el8_3 |
| Red Hat:enterprise_linux:8::baseos | openssl-perl | before 1:1.1.1g-15.el8_3 | 1:1.1.1g-15.el8_3 |
| Red Hat:jboss_core_services:1::el7 | jbcs-httpd24-httpd | before 0:2.4.37-70.jbcs.el7 | 0:2.4.37-70.jbcs.el7 |
| Red Hat:jboss_core_services:1::el7 | jbcs-httpd24-httpd-debuginfo | before 0:2.4.37-70.jbcs.el7 | 0:2.4.37-70.jbcs.el7 |
| Red Hat:jboss_core_services:1::el7 | jbcs-httpd24-httpd-devel | before 0:2.4.37-70.jbcs.el7 | 0:2.4.37-70.jbcs.el7 |
| Red Hat:jboss_core_services:1::el7 | jbcs-httpd24-httpd-manual | before 0:2.4.37-70.jbcs.el7 | 0:2.4.37-70.jbcs.el7 |
| Red Hat:jboss_core_services:1::el7 | jbcs-httpd24-httpd-selinux | before 0:2.4.37-70.jbcs.el7 | 0:2.4.37-70.jbcs.el7 |
+59
Same product
openssl: all recordsOther highest-scoring records for the same primary product.
- CVE-2014-0160The (1) TLS and (2) DTLS implementations in OpenSSL 1.0.1 before 1.0.1g do not properly handle Heartbeat Extension packets, which allows remKEV90Now
- CVE-2021-3711SM2 Decryption Buffer Overflow65This week
- CVE-2003-0545Double free vulnerability in OpenSSL 0.9.7 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code 65This week
Published before and after this one in the same product
- ← EarlierCVE-2021-23840Feb 16, 2021 · Integer overflow in CipherUpdate45Plan
- ← EarlierCVE-2021-23841Feb 16, 2021 · Null pointer deref in X509_issuer_and_serial_hash()25Monitor
- Later →CVE-2021-3450Mar 25, 2021 · CA certificate check bypass with X509_V_FLAG_X509_STRICT35Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| alpine:openssl | 1.1.1k-r0 · Alpine:v3.10 | Package registry (OSV) |
| alpine:openssl3 | 1.1.1k-r0 · Alpine:v3.15 | Package registry (OSV) |
| crates.io:openssl-src | 111.15.0 | Package registry (OSV) |
| debian:openssl | 1.1.1k-1 · Debian:12 | Package registry (OSV) |
| opensuse:matrix-synapse | 1.43.0-1.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| opensuse:nodejs10 | 10.24.1-lp152.2.15.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| opensuse:nodejs12 | 12.22.2-lp152.3.15.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| opensuse:openssl-1_1 | 1.1.1d-lp152.7.15.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| red hat:jbcs-httpd24-httpd | 0:2.4.37-70.jbcs.el7 · Red Hat:jboss_core_services:1::el7 | Package registry (OSV) |
| red hat:jws5-tomcat-native | 0:1.2.25-4.redhat_4.el7jws · Red Hat:jboss_enterprise_web_server:5.4::el7 | Package registry (OSV) |
| red hat:jws5-tomcat-native-debuginfo | 0:1.2.25-4.redhat_4.el7jws · Red Hat:jboss_enterprise_web_server:5.4::el7 | Package registry (OSV) |
| red hat:openssl | 1:1.1.1g-15.el8_3 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:openssl-debuginfo | 1:1.1.1g-15.el8_3 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:openssl-debugsource | 1:1.1.1g-15.el8_3 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:openssl-devel | 1:1.1.1g-15.el8_3 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:openssl-libs | 1:1.1.1g-15.el8_3 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:openssl-libs-debuginfo | 1:1.1.1g-15.el8_3 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:openssl-perl | 1:1.1.1g-15.el8_3 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:redhat-virtualization-host | 0:4.4.5-20210330.0.el8_3 · Red Hat:rhev_hypervisor:4.4::el8 | Package registry (OSV) |
| red hat:redhat-virtualization-host-image-update | 0:4.4.5-20210330.0.el8_3 · Red Hat:rhev_hypervisor:4.4::el8 | Package registry (OSV) |
| rocky linux:openssl | 1:1.1.1g-15.el8_3 · Rocky Linux:8 | Package registry (OSV) |
| suse:nodejs10 | 10.24.1-1.39.1 · SUSE:Linux Enterprise Module for Web and Scripting 12 | Package registry (OSV) |
| suse:nodejs12 | 12.22.2-1.32.1 · SUSE:Linux Enterprise Module for Web and Scripting 12 | Package registry (OSV) |
| suse:openssl-1_1 | 1.1.1d-2.33.1 · SUSE:OpenStack Cloud 9 | Package registry (OSV) |
Exploit status
Proof of concept available
A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.
Evidence
- Proof-of-concept repository on GitHub ×1
Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.
| Source | Kind | Date |
|---|---|---|
| Proof-of-concept repository on GitHub | stars:224 | 2021-03-26 |
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
- Published
- First PoCsame day
- TodayOct 27, 2026+2042 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.
National notice (Türkiye Cybersecurity Directorate / USOM)
Official security notices citing this record; remediation advice is on the agency's page.
- TR-22-0351 · May 13, 2022(Siemens Güvenlik Bildirimi)
- TR-22-0215 · Mar 11, 2022(Siemens Güvenlik Bildirimi)
- TR-22-0020 · Jan 10, 2022(IBM Güvenlik Bülteni)
- TR-21-0964 · Dec 3, 2021(Hitachi Güvenlik Zafiyeti)
- TR-21-0622 · Aug 9, 2021(IBM Güvenlik Bülteni Yayınladı)
- TR-21-0612 · Aug 5, 2021(IBM Güvenlik Bülteni Yayınladı)
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- Special conditions such as timing or configuration are required.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-476 · NULL Pointer DereferenceCVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
- SSVC exploitation— → none
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (19 more)Show less
- www.openwall.com/lists/oss-security/2021/03/27/2
- www.openwall.com/lists/oss-security/2021/03/28/3
- www.openwall.com/lists/oss-security/2021/03/28/4
- cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
- cert-portal.siemens.com/productcert/pdf/ssa-772220.pdf
- git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=fb9fa6b51defd48157eeb207f52181f735d96148
- kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44845
- kc.mcafee.com/corporate/index?page=content&id=SB10356
- lists.debian.org/debian-lts-announce/2021/08/msg00029.html
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CCBFLLVQVILIVGZMBJL3IXZGKWQISYNP/
- psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0013
- security.FreeBSD.org/advisories/FreeBSD-SA-21:07.openssl.asc
- security.gentoo.org/glsa/202103-03
- security.netapp.com/advisory/ntap-20210326-0006/
- security.netapp.com/advisory/ntap-20210513-0002/
- security.netapp.com/advisory/ntap-20240621-0006/
- tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-openssl-2021-GHY28dJd
- www.debian.org/security/2021/dsa-4875
- www.openssl.org/news/secadv/20210325.txt
Vendor advisories and official records. Exploit/PoC links are deliberately left out.