CVE-2021-3449

HIGHNVD 5.97.8▲
EchelonGraph scoreHIGH confidence

Score elevated to 7.8 because EPSS predicts 64% probability of exploitation within the next 30 days (99th percentile of EPSS-scored CVEs). NVD baseline CVSS 5.9 retained for reference. Confidence: see factors.

Triggered by: EPSS exploit prediction (continuous uplift above 30%)
Sources: epss, nvd
Trending — 3 sources updated this weekElevated
7.8EG
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • High exploitation likelihood — EPSS 64%
CISA-KEV: Not listedEPSS PROB: 64%CVSS: 5.9Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

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).

CVSS v3
5.9
EG Score
7.8HIGHhigh confidence
EG Risk
76
EG Risk 76/100CISA 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
Severity78% × 45%
Exploitation64% × 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
64%
EPSS %ILE
99th
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 partial (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.
genericMentions a patch (unverified)

[SECURITY] [DLA 2751-1] postgresql-9.6 security update

https://lists.debian.org/debian-lts-announce/2021/08/msg00029.html
generic
https://cert-portal.siemens.com/productcert/pdf/ssa-772220.pdf
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-2021-3449(1)

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

Patch Availability(11)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulibecpg-compat3 (13.4-0ubuntu0.21.04.1) @ hirsute2026-10-08ubuntu
ubuntuopenssl (1.1.1f-1ubuntu4.3) @ groovy2026-10-08ubuntu
redhatjws5-tomcat-native-0:1.2.25-4.redhat_4.el8jws2021-04-14redhat
redhatpatch2021-04-14redhat
redhattomcat-native-0:1.2.23-24.redhat_24.ep7.el72021-04-14redhat
redhatjbcs-httpd24-openssl-pkcs11-0:0.4.10-20.jbcs.el72021-04-14redhat
redhatredhat-virtualization-host-0:4.4.5-20210330.0.el8_32021-04-14redhat
redhatopenssl2021-04-14redhat
redhatopenssl-1:1.1.1c-5.el8_12021-04-07redhat
redhatopenssl-1:1.1.1c-18.el8_22021-04-05redhat
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

(24 across 22 ecosystems)
Alpine:v3.15(2)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1 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—
  • 1.1.1 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—
  • 1.1.1 up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.11(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1 up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.12(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1 up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.13(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1 up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.14(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1 up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.17(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1 up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.18(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1 up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.19(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1 up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.20(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1 up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.21(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1 up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.22(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1 up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.23(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1 up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.24(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1 up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
Alpine:v3.9(1)
PackageVulnerable rangeFix by version rangeDependents
openssl—
  • 1.1.1 up to 1.1.1k-r0: fixed in 1.1.1k-r0
—
crates.io(1)
PackageVulnerable rangeFix by version rangeDependents
openssl-src—
  • every version up to 111.15.0: fixed in 111.15.0
  • 0.0.0-0 up to 111.15.0: fixed in 111.15.0
—
Debian:10(1)
PackageVulnerable rangeFix by version rangeDependents
openssl1.1.1c-1 ... 1.1.1d-0+deb10u5 (6 versions)
  • every version up to 1.1.1d-0+deb10u6: fixed in 1.1.1d-0+deb10u6
—
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

(12)

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 6× in last 7d / 27× 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 141 total refreshes for this CVE.

  1. 2026-10-09 20:04 UTCEPSS rescore
  2. 2026-10-08 22:28 UTCVendor advisory
  3. 2026-10-08 21:33 UTCEG score recompute
  4. 2026-10-08 21:33 UTCVendor advisory
  5. 2026-10-07 23:45 UTCEPSS rescore
  6. 2026-10-06 15:14 UTCEPSS rescore
  7. 2026-10-02 16:23 UTCEPSS rescore
  8. 2026-10-01 19:46 UTCEPSS rescore
  9. 2026-09-30 15:37 UTCEG score recompute
  10. 2026-09-30 15:00 UTCEPSS rescore
  11. 2026-09-28 13:47 UTCEPSS rescore
  12. 2026-09-27 13:41 UTCEPSS rescore
  13. 2026-09-26 15:54 UTCEPSS rescore
  14. 2026-09-26 05:55 UTCOSV refresh
  15. 2026-09-24 14:00 UTCEPSS rescore
  16. 2026-09-24 14:00 UTCEPSS rescore
  17. 2026-09-23 13:44 UTCEPSS rescore
  18. 2026-09-22 14:44 UTCEPSS rescore
  19. 2026-09-21 20:28 UTCEPSS rescore
  20. 2026-09-20 20:13 UTCEPSS rescore
  21. 2026-09-18 19:23 UTCEPSS rescore
  22. 2026-09-17 19:23 UTCEPSS rescore
  23. 2026-09-17 19:23 UTCEPSS rescore
  24. 2026-09-16 14:05 UTCEPSS rescore
  25. 2026-09-15 03:06 UTCEPSS rescore
Show 75 more
  1. 2026-09-12 14:57 UTCEPSS rescore
  2. 2026-09-11 09:33 UTCEPSS rescore
  3. 2026-09-08 21:56 UTCEPSS rescore
  4. 2026-09-06 20:31 UTCOSV refresh
  5. 2026-09-06 13:45 UTCEPSS rescore
  6. 2026-09-05 15:25 UTCEPSS rescore
  7. 2026-09-04 13:57 UTCEPSS rescore
  8. 2026-09-02 14:09 UTCEPSS rescore
  9. 2026-09-01 13:50 UTCEPSS rescore
  10. 2026-09-01 03:33 UTCEPSS rescore
  11. 2026-08-30 19:14 UTCEPSS rescore
  12. 2026-08-30 19:14 UTCEPSS rescore
  13. 2026-08-28 21:37 UTCEPSS rescore
  14. 2026-08-27 14:22 UTCEPSS rescore
  15. 2026-08-26 14:43 UTCEPSS rescore
  16. 2026-08-25 13:46 UTCEPSS rescore
  17. 2026-08-24 14:13 UTCEPSS rescore
  18. 2026-08-21 23:46 UTCEPSS rescore
  19. 2026-08-20 22:52 UTCEPSS rescore
  20. 2026-08-20 22:52 UTCEPSS rescore
  21. 2026-08-20 06:34 UTCOSV refresh
  22. 2026-08-19 17:01 UTCEPSS rescore
  23. 2026-08-18 13:45 UTCEPSS rescore
  24. 2026-08-17 13:44 UTCEPSS rescore
  25. 2026-08-16 14:53 UTCEPSS rescore
  26. 2026-08-16 02:11 UTCEPSS rescore
  27. 2026-08-15 01:27 UTCEPSS rescore
  28. 2026-08-13 21:57 UTCEPSS rescore
  29. 2026-08-12 13:48 UTCEPSS rescore
  30. 2026-08-11 13:38 UTCEPSS rescore
  31. 2026-08-07 16:24 UTCEPSS rescore
  32. 2026-08-05 19:14 UTCEPSS rescore
  33. 2026-08-05 01:40 UTCOSV refresh
  34. 2026-07-30 16:25 UTCEPSS rescore
  35. 2026-07-30 01:28 UTCEPSS rescore
  36. 2026-07-28 15:33 UTCEPSS rescore
  37. 2026-07-26 14:52 UTCEPSS rescore
  38. 2026-07-26 14:52 UTCEPSS rescore
  39. 2026-07-25 14:15 UTCEPSS rescore
  40. 2026-07-24 14:15 UTCEPSS rescore
  41. 2026-07-23 14:16 UTCEPSS rescore
  42. 2026-07-23 02:01 UTCEG score recompute▲ 1.90
  43. 2026-07-22 22:48 UTCEG score recompute
  44. 2026-07-22 14:06 UTCEPSS rescore
  45. 2026-07-21 15:22 UTCEPSS rescore
  46. 2026-07-21 15:22 UTCEPSS rescore
  47. 2026-07-20 17:05 UTCEPSS rescore
  48. 2026-07-19 02:27 UTCEPSS rescore
  49. 2026-07-18 23:29 UTCOSV refresh
  50. 2026-07-16 17:00 UTCEPSS rescore
  51. 2026-07-16 17:00 UTCEPSS rescore
  52. 2026-07-15 16:55 UTCEPSS rescore
  53. 2026-07-15 16:55 UTCEPSS rescore
  54. 2026-07-13 22:27 UTCEPSS rescore
  55. 2026-07-13 22:27 UTCEPSS rescore
  56. 2026-07-13 06:11 UTCEPSS rescore
  57. 2026-07-13 06:11 UTCEPSS rescore
  58. 2026-07-11 08:25 UTCEPSS rescore
  59. 2026-07-11 08:25 UTCEPSS rescore
  60. 2026-07-09 19:07 UTCEPSS rescore
  61. 2026-07-05 02:28 UTCEPSS rescore
  62. 2026-07-05 02:28 UTCEPSS rescore
  63. 2026-07-02 16:57 UTCEPSS rescore
  64. 2026-07-01 15:04 UTCEPSS rescore
  65. 2026-07-01 06:48 UTCOSV refresh
  66. 2026-06-28 04:54 UTCEPSS rescore
  67. 2026-06-28 04:54 UTCEPSS rescore
  68. 2026-06-27 03:06 UTCEPSS rescore
  69. 2026-06-27 03:06 UTCEPSS rescore
  70. 2026-06-25 13:48 UTCEPSS rescore
  71. 2026-06-25 13:48 UTCEPSS rescore
  72. 2026-06-23 21:31 UTCEPSS rescore
  73. 2026-06-23 21:31 UTCEPSS rescore
  74. 2026-06-21 01:58 UTCEPSS rescore
  75. 2026-06-21 01:58 UTCEPSS rescore

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 GitHub PoC). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCriptl/cve-2021-3449
    First seen Mar 26, 2021

    CVE-2021-3449 OpenSSL denial-of-service exploit 👨🏻‍💻

    Open source ↗

Related CVEs(same product + same vendor + same CWE)

Same vendor

2 shown

redhat:RHSA-2021:1024 · ubuntu:USN-5038-1

Frequently asked(5)

What is CVE-2021-3449?
CVE-2021-3449 is a high vulnerability published on March 25, 2021. 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 signaturealgorithms extension (where it was present in the initial ClientHello), but includes a signaturealgorithms_cert extension then a…
When was CVE-2021-3449 disclosed?
CVE-2021-3449 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-2021-3449 actively exploited?
CVE-2021-3449 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 64% probability of exploitation in the next 30 days (99th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2021-3449?
CVE-2021-3449 has a CVSS v3 base score of 5.9 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 7.8 (HIGH).
How do I remediate CVE-2021-3449?
A fix for CVE-2021-3449 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2021-3449 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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