CVE-2021-3450

HIGHNVD 7.47.4—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.4 under NVD CVSS v3. EPSS exploit probability: 18% (97th percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Trending — 3 sources updated this weekElevated
7.4EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 18%CVSS: 7.4Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

The X509_V_FLAG_X509_STRICT flag enables additional security checks of the certificates present in a certificate chain. It is not set by default. Starting from OpenSSL version 1.1.1h a check to disallow certificates in the chain that have explicitly encoded elliptic curve parameters was added as an additional strict check. An error in the implementation of this check meant that the result of a previous check to confirm that certificates in the chain are valid CA certificates was overwritten. This effectively bypasses the check that non-CA certificates must not be able to issue other certificates. If a "purpose" has been configured then there is a subsequent opportunity for checks that the certificate is a valid CA. All of the named "purpose" values implemented in libcrypto perform this check. Therefore, where a purpose is set the certificate chain will still be rejected even when the strict flag has been used. A purpose is set by default in libssl client and server certificate verification routines, but it can be overridden or removed by an application. In order to be affected, an application must explicitly set the X509_V_FLAG_X509_STRICT verification flag and either not set a purpose for the certificate verification or, in the case of TLS client or server applications, override the default purpose. OpenSSL versions 1.1.1h and newer 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 1.1.1h-1.1.1j).

CVSS v3
7.4
EG Score
7.4HIGHmedium confidence
EG Risk
64
EG Risk 64/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity74% × 45%
Exploitation40% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
18%
EPSS %ILE
97th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

March 25, 2021

Last Modified

October 8, 2026

Advisory Details (7)

Auto-updated Oct 8, 2026
Patch available.
generic

OpenSSL Security Advisory

https://mta.openssl.org/pipermail/openssl-announce/2021-March/000198.html
generic

[SECURITY] Fedora 34 Update: openssl-1.1.1k-1.fc34 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CCBFLLVQVILIVGZMBJL3IXZGKWQISYNP/
generic
https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
generic

oss-security - Re: OpenSSL 1.1.1 CVE-2021-3450 CA certificate check bypass with X509_V_FLAG_X509_STRICT, CVE-2021-3449 NULL pointer deref in signature_algorithms processing

http://www.openwall.com/lists/oss-security/2021/03/28/4
generic

oss-security - Re: OpenSSL 1.1.1 CVE-2021-3450 CA certificate check bypass with X509_V_FLAG_X509_STRICT, CVE-2021-3449 NULL pointer deref in signature_algorithms processing

http://www.openwall.com/lists/oss-security/2021/03/28/3
generic

oss-security - Re: OpenSSL 1.1.1 CVE-2021-3450 CA certificate check bypass with X509_V_FLAG_X509_STRICT, CVE-2021-3449 NULL pointer deref in signature_algorithms processing

http://www.openwall.com/lists/oss-security/2021/03/27/2
generic

oss-security - OpenSSL 1.1.1 CVE-2021-3450 CA certificate check bypass with X509_V_FLAG_X509_STRICT, CVE-2021-3449 NULL pointer deref in signature_algorithms processing

http://www.openwall.com/lists/oss-security/2021/03/27/1

Vendor Advisories for CVE-2021-3450(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(7)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatjbcs-httpd24-openssl-pkcs11-0:0.4.10-20.jbcs.el72021-04-14redhat
redhatopenssl2021-04-14redhat
redhattomcat-native-0:1.2.23-24.redhat_24.ep7.el72021-04-14redhat
redhatpatch2021-04-14redhat
redhatjws5-tomcat-native-0:1.2.25-4.redhat_4.el8jws2021-04-14redhat
redhatredhat-virtualization-host-0:4.4.5-20210330.0.el8_32021-04-14redhat
redhatopenssl-1:1.1.1g-15.el8_32021-03-30redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(23 across 21 ecosystems)
Alpine:v3.15(2)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1h up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
openssl3—
  • every version up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.16(2)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1h up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
openssl3—
  • every version up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.10(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1h up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.11(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1h up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.12(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1h up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.13(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1h up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.14(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1h up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.17(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1h up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.18(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1h up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.19(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1h up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.20(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1h up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.21(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1h up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.22(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1h up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.23(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1h up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.24(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1h up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.9(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1h up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
crates.io(1)
PackageVulnerable rangeFix by version rangeDependents
openssl-src—
  • 111.11.0 up to 111.15.0: fixed in 111.15.0
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • every version up to 1.1.1k-1: fixed in 1.1.1k-1
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • every version up to 1.1.1k-1: fixed in 1.1.1k-1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • every version up to 1.1.1k-1: fixed in 1.1.1k-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • every version up to 1.1.1k-1: fixed in 1.1.1k-1
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(8)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 8× in last 7d / 31× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 175 total refreshes for this CVE.

  1. 2026-10-09 20:04 UTCEPSS rescore
  2. 2026-10-08 21:24 UTCEG score recompute
  3. 2026-10-08 21:24 UTCVendor advisory
  4. 2026-10-08 16:40 UTCEPSS rescore
  5. 2026-10-07 23:45 UTCEPSS rescore
  6. 2026-10-06 15:14 UTCEPSS rescore
  7. 2026-10-05 17:40 UTCEPSS rescore
  8. 2026-10-03 14:22 UTCEPSS rescore
  9. 2026-10-02 16:23 UTCEPSS rescore
  10. 2026-10-01 19:46 UTCEPSS rescore
  11. 2026-09-30 15:37 UTCEG score recompute
  12. 2026-09-30 15:00 UTCEPSS rescore
  13. 2026-09-29 15:15 UTCEPSS rescore
  14. 2026-09-27 13:41 UTCEPSS rescore
  15. 2026-09-26 15:54 UTCEPSS rescore
  16. 2026-09-26 05:25 UTCOSV refresh
  17. 2026-09-26 00:21 UTCEPSS rescore
  18. 2026-09-24 14:00 UTCEPSS rescore
  19. 2026-09-24 14:00 UTCEPSS rescore
  20. 2026-09-23 13:44 UTCEPSS rescore
  21. 2026-09-22 14:44 UTCEPSS rescore
  22. 2026-09-21 20:28 UTCEPSS rescore
  23. 2026-09-19 15:38 UTCEPSS rescore
  24. 2026-09-18 19:23 UTCEPSS rescore
  25. 2026-09-17 19:23 UTCEPSS rescore
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  1. 2026-09-17 19:23 UTCEPSS rescore
  2. 2026-09-16 14:05 UTCEPSS rescore
  3. 2026-09-15 03:06 UTCEPSS rescore
  4. 2026-09-12 14:57 UTCEPSS rescore
  5. 2026-09-11 14:49 UTCEPSS rescore
  6. 2026-09-11 09:33 UTCEPSS rescore
  7. 2026-09-08 21:56 UTCEPSS rescore
  8. 2026-09-07 15:58 UTCEPSS rescore
  9. 2026-09-06 20:13 UTCOSV refresh
  10. 2026-09-06 13:45 UTCEPSS rescore
  11. 2026-09-05 15:25 UTCEPSS rescore
  12. 2026-09-04 13:57 UTCEPSS rescore
  13. 2026-09-04 05:03 UTCEPSS rescore
  14. 2026-09-02 14:09 UTCEPSS rescore
  15. 2026-09-01 13:50 UTCEPSS rescore
  16. 2026-09-01 03:33 UTCEPSS rescore
  17. 2026-08-30 19:14 UTCEPSS rescore
  18. 2026-08-30 19:14 UTCEPSS rescore
  19. 2026-08-30 01:19 UTCEPSS rescore
  20. 2026-08-28 21:37 UTCEPSS rescore
  21. 2026-08-27 14:22 UTCEPSS rescore
  22. 2026-08-26 14:43 UTCEPSS rescore
  23. 2026-08-25 13:46 UTCEPSS rescore
  24. 2026-08-24 14:13 UTCEPSS rescore
  25. 2026-08-23 00:16 UTCEPSS rescore
  26. 2026-08-21 23:46 UTCEPSS rescore
  27. 2026-08-20 22:52 UTCEPSS rescore
  28. 2026-08-20 22:52 UTCEPSS rescore
  29. 2026-08-20 06:15 UTCOSV refresh
  30. 2026-08-19 17:01 UTCEPSS rescore
  31. 2026-08-18 13:45 UTCEPSS rescore
  32. 2026-08-17 13:44 UTCEPSS rescore
  33. 2026-08-16 14:53 UTCEPSS rescore
  34. 2026-08-16 02:11 UTCEPSS rescore
  35. 2026-08-15 01:27 UTCEPSS rescore
  36. 2026-08-13 21:57 UTCEPSS rescore
  37. 2026-08-12 13:48 UTCEPSS rescore
  38. 2026-08-11 13:38 UTCEPSS rescore
  39. 2026-08-08 16:33 UTCEPSS rescore
  40. 2026-08-07 16:24 UTCEPSS rescore
  41. 2026-08-06 13:44 UTCEPSS rescore
  42. 2026-08-05 19:14 UTCEPSS rescore
  43. 2026-08-05 01:40 UTCOSV refresh
  44. 2026-08-03 10:33 UTCEPSS rescore
  45. 2026-08-01 04:13 UTCEPSS rescore
  46. 2026-07-30 16:25 UTCEPSS rescore
  47. 2026-07-30 01:28 UTCEPSS rescore
  48. 2026-07-28 15:33 UTCEPSS rescore
  49. 2026-07-26 14:52 UTCEPSS rescore
  50. 2026-07-26 14:52 UTCEPSS rescore
  51. 2026-07-25 14:15 UTCEPSS rescore
  52. 2026-07-24 14:15 UTCEPSS rescore
  53. 2026-07-23 14:16 UTCEPSS rescore
  54. 2026-07-23 02:01 UTCEG score recompute
  55. 2026-07-22 22:48 UTCEG score recompute
  56. 2026-07-22 14:06 UTCEPSS rescore
  57. 2026-07-21 15:22 UTCEPSS rescore
  58. 2026-07-21 15:22 UTCEPSS rescore
  59. 2026-07-20 17:05 UTCEPSS rescore
  60. 2026-07-19 02:27 UTCEPSS rescore
  61. 2026-07-18 23:29 UTCOSV refresh
  62. 2026-07-18 10:02 UTCEPSS rescore
  63. 2026-07-18 10:02 UTCEPSS rescore
  64. 2026-07-16 17:00 UTCEPSS rescore
  65. 2026-07-16 17:00 UTCEPSS rescore
  66. 2026-07-15 16:55 UTCEPSS rescore
  67. 2026-07-15 16:55 UTCEPSS rescore
  68. 2026-07-15 01:58 UTCEPSS rescore
  69. 2026-07-13 22:27 UTCEPSS rescore
  70. 2026-07-13 22:27 UTCEPSS rescore
  71. 2026-07-12 05:44 UTCEPSS rescore
  72. 2026-07-11 08:25 UTCEPSS rescore
  73. 2026-07-11 08:25 UTCEPSS rescore
  74. 2026-07-09 19:07 UTCEPSS rescore
  75. 2026-07-08 15:12 UTCEPSS rescore

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redhat:RHSA-2021:1024

Frequently asked(5)

What is CVE-2021-3450?
CVE-2021-3450 is a high vulnerability published on March 25, 2021. The X509VFLAGX509STRICT flag enables additional security checks of the certificates present in a certificate chain. It is not set by default. Starting from OpenSSL version 1.1.1h a check to disallow certificates in the chain that have explicitly encoded elliptic curve parameters was added as an…
When was CVE-2021-3450 disclosed?
CVE-2021-3450 was first published on March 25, 2021, with the most recent update on October 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-3450 actively exploited?
CVE-2021-3450 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 18% probability of exploitation in the next 30 days (97th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2021-3450?
CVE-2021-3450 has a CVSS v3 base score of 7.4 (NVD).
How do I remediate CVE-2021-3450?
A fix for CVE-2021-3450 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2021-3450 are linked in the Vendor Advisories panel on this page.

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