CVE-2026-74900

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-08-17. The CNA's CVSS baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:vulncheck, epss, ghsa
Trending — 3 sources updated this week
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.6%CVSS: 9.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

openssl_encrypt versions before 1.4.0 contain a critical vulnerability in pqc.py where KEM decapsulation failures silently fall back to simulation mode, generating a deterministic shared secret from only 16 bytes of the private key and publicly available encapsulated key data. Attackers who obtain 16 bytes of the private key can compute the shared secret and decrypt all ciphertext, as the fallback triggers on any KEM failure without raising an error.

CVSS v3
9.8
EG Score
9.8CRITICALmedium confidence
EG Risk
59
EG Risk 59/100CISA 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
Severity98% × 45%
Exploitation1% × 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
0.6%
EPSS %ILE
44th
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

August 17, 2026

Last Modified

October 1, 2026

Advisory Details (2)

Auto-updated Oct 1, 2026
Patch available. Sources: github.
generic

openssl_encrypt before 1.4.0 Weak Shared Secret via PQC Simulation Mode | Advisories | VulnCheck

https://www.vulncheck.com/advisories/openssl-encrypt-before-weak-shared-secret-via-pqc-simulation-mode
github Patch Available

PQC simulation mode fallback uses weak deterministic shared secret · Advisory · jahlives/openssl_encrypt · GitHub

https://github.com/jahlives/openssl_encrypt/security/advisories/GHSA-p3gq-pcg9-qvfv

Vendor Advisories for CVE-2026-74900(1)

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

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFix by version rangeDependents
openssl-encrypt0.2.2 ... 1.4.0b8 (44 versions)
  • every version up to 1.4.0: fixed in 1.4.0
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 40× in last 7d / 184× 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 329 total refreshes for this CVE.

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

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Frequently asked(5)

What is CVE-2026-74900?
CVE-2026-74900 is a critical vulnerability published on August 17, 2026. openssl_encrypt versions before 1.4.0 contain a critical vulnerability in pqc.py where KEM decapsulation failures silently fall back to simulation mode, generating a deterministic shared secret from only 16 bytes of the private key and publicly available encapsulated key data. Attackers who obtain…
When was CVE-2026-74900 disclosed?
CVE-2026-74900 was first published on August 17, 2026, with the most recent update on October 1, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-74900 actively exploited?
CVE-2026-74900 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.6% probability of exploitation in the next 30 days (44th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-74900?
CVE-2026-74900 has a CVSS base score of 9.8 (the CNA's own assessment, by vulncheck; NVD's own analysis pending).
How do I remediate CVE-2026-74900?
A fix for CVE-2026-74900 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-74900 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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