In the cryptography package before 3.3.2 for Python, certain sequences of update calls to symmetrically encrypt multi-GB values could result in an integer overflow and buffer overflow, as demonstrated by the Fernet class.
CVE-2020-36242
This critical-severity CVE scores 9.1 under NVD CVSS v3. EPSS exploit probability: 6.7%, top 7% of all CVEs by exploit prediction. 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).
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 9.1
- EG Score
- 9.1(medium)
- EG Risk
- 48(Track)EG Risk 48/100SSVC: Track
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 computedSeverity91% × 45%Exploitation7% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 7%
- EPSS %ILE
- 93%
- KEV
- Not listed
Published
February 7, 2021
Last Modified
November 21, 2024
Advisory Details (4)
Auto-updated Jul 22, 2026[SECURITY] Fedora 33 Update: python-cryptography-3.2.1-2.fc33 - package-announce - Fedora mailing-lists
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L7RGQLK4J5ZQFRLKCHVVG6BKZTUQMG7E/Fernet fails to encrypt/decrypt large data · Issue #5615 · pyca/cryptography · GitHub
https://github.com/pyca/cryptography/issues/5615Comparing 3.3.1...3.3.2 · pyca/cryptography · GitHub
https://github.com/pyca/cryptography/compare/3.3.1...3.3.2cryptography/CHANGELOG.rst at main · pyca/cryptography · GitHub
https://github.com/pyca/cryptography/blob/master/CHANGELOG.rstVendor Advisories for CVE-2020-36242(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Patch Availability(3)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| redhat | rh-python38-python-urllib3-0:1.25.7-7.el7 | 2021-08-24 | redhat |
| redhat | redhat-virtualization-host-0:4.4.6-20210527.3.el8_4 | 2021-06-03 | redhat |
| redhat | python-cryptography-0:3.2.1-4.el8 | 2021-05-18 | redhat |
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
(8 across 8 ecosystems)
Alpine:v3.13(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| py3-cryptography | — | 3.3.2-r0 | — |
Alpine:v3.23(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| py3-cryptography | — | 3.2.2-r0 | — |
Alpine:v3.24(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| py3-cryptography | — | 3.2.2-r0 | — |
Debian:11(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| python-cryptography | — | 3.3.2-1 | — |
Debian:12(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| python-cryptography | — | 3.3.2-1 | — |
Debian:13(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| python-cryptography | — | 3.3.2-1 | — |
Debian:14(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| python-cryptography | — | 3.3.2-1 | — |
PyPI(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| cryptography | 3.1 ... 3.3.1 (6 versions) | 3.3.2 | — |
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Additional Vendor Advisories
(3)
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.
- Microsoft MSRCCVE-2020-362422021-02-10
In the cryptography package before 3.3.2 for Python certain sequences of update calls to symmetrically encrypt multi-GB values could result in an integer overflow and buffer overflow as demonstrated by the Fernet class.
- Red HatRHSA-2021:1608MODERATE2020-12-09
RHSA-2021:1608 — Moderate
- Red HatRHSA-2021:2239MODERATE2020-12-09
RHSA-2021:2239 — Moderate
Data Freshness Timeline
(refreshed 5× in last 7d / 22× 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 116 total refreshes for this CVE.
- 2026-08-25 13:45 UTCEPSS rescore
- 2026-08-21 23:45 UTCEPSS rescore
- 2026-08-20 22:52 UTCEPSS rescore
- 2026-08-20 08:31 UTCOSV refresh
- 2026-08-19 17:00 UTCEPSS rescore
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- 2026-08-06 13:43 UTCEPSS rescore
- 2026-08-05 04:10 UTCOSV refresh
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- 2026-07-23 14:15 UTCEPSS rescore
- 2026-07-23 14:15 UTCEPSS rescore
- 2026-07-23 01:53 UTCEG score recompute
- 2026-07-22 22:39 UTCEG score recompute
- 2026-07-22 14:05 UTCEPSS rescore
- 2026-07-21 15:22 UTCEPSS rescore
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- 2026-07-19 02:26 UTCEPSS rescore
- 2026-07-19 02:26 UTCEPSS rescore
- 2026-07-19 02:22 UTCOSV refresh
- 2026-07-16 16:59 UTCEPSS rescore
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- 2026-07-09 19:07 UTCEPSS rescore
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- 2026-07-07 13:43 UTCEPSS rescore
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- 2026-07-04 06:29 UTCEPSS rescore
- 2026-07-04 06:29 UTCEPSS rescore
- 2026-07-01 09:18 UTCOSV refresh
- 2026-06-30 23:20 UTCEPSS rescore
- 2026-06-30 23:20 UTCEPSS rescore
- 2026-06-29 14:04 UTCEPSS rescore
- 2026-06-28 04:54 UTCEPSS rescore
- 2026-06-28 04:54 UTCEPSS rescore
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- 2026-06-25 13:48 UTCEPSS rescore
- 2026-06-24 14:03 UTCEPSS rescore
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- 2026-06-23 21:31 UTCEPSS rescore
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- 2026-06-21 14:54 UTCEPSS rescore
- 2026-06-21 14:54 UTCEPSS rescore
- 2026-06-19 19:24 UTCEPSS rescore
- 2026-06-19 19:23 UTCEPSS rescore
- 2026-06-18 17:50 UTCEPSS rescore
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- 2026-06-17 17:50 UTCEPSS rescore
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- 2026-06-15 17:46 UTCEPSS rescore
- 2026-06-14 23:15 UTCEPSS rescore
- 2026-06-13 22:58 UTCEPSS rescore
- 2026-06-13 14:43 UTCOSV refresh
- 2026-06-12 23:10 UTCEPSS rescore
- 2026-06-11 13:58 UTCEPSS rescore
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- 2026-06-04 13:10 UTCEPSS rescore
- 2026-06-02 20:11 UTCEPSS rescore
- 2026-06-02 20:11 UTCEPSS rescore
Frequently asked(5)
What is CVE-2020-36242?
When was CVE-2020-36242 disclosed?
Is CVE-2020-36242 actively exploited?
What is the CVSS score of CVE-2020-36242?
How do I remediate CVE-2020-36242?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2020-36242
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