NVD / CVE Program· CNA redhat

CVE-2020-25659: python-cryptography 3.2 is vulnerable to Bleichenbacher timing attacks in the RSA decryption API, via timed processing of valid PKCS#1 v1.5…

MediumCVSS 5.9 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 24/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 2.4% (FIRST EPSS); higher than 84.6% 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.
Fixed version: py3-cryptography (Alpine:v3.13) 3.2.1-r0; python-cryptography (Debian:12) 3.2.1-1; python-cryptography (openSUSE:Leap 15.2) 2.8-lp152.2.3.1.
Mentioned 2 times in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to py3-cryptography (Alpine:v3.13) 3.2.1-r0; python-cryptography (Debian:12) 3.2.1-1; python-cryptography (openSUSE:Leap 15.2) 2.8-lp152.2.3.1 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

python-cryptography 3.2 is vulnerable to Bleichenbacher timing attacks in the RSA decryption API, via timed processing of valid PKCS#1 v1.5 ciphertext.

Pre-auth

Published: Jan 11, 2021
Updated: Jun 16, 2026
EPSS: 2.4% · 84th percentile
CWE: CWE-385

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 23 / 40 · 5.9 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 1 / 30 · 2.4%

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Not in KEV: no record of exploitation in the wild
No public exploit code on record
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Noroxi analysis

What does it mean in your environment?

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Affected 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
cryptography.io	cryptography	cpe:2.3:a:cryptography.io:cryptography
oracle	communications cloud native core network function cloud native environment	cpe:2.3:a:oracle:communications_cloud_native_core_network_function_cloud_native_environment

Versions reported by the vendor

Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.

n/a python-cryptography
- python-cryptography 3.2affected

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

cryptography.io cryptography3.2
oracle communications cloud native core network function cloud native environment1.10.0

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Alpine:v3.13	py3-cryptography	before 3.2.1-r0	3.2.1-r0
Debian:12	python-cryptography	before 3.2.1-1	3.2.1-1
openSUSE:Leap 15.2	python-cryptography	before 2.8-lp152.2.3.1	2.8-lp152.2.3.1
openSUSE:Leap 15.4	azure-cli-core	before 2.17.1-150100.6.18.1	2.17.1-150100.6.18.1
openSUSE:Leap 15.4	python-constantly	before 15.1.0-150000.3.4.1	15.1.0-150000.3.4.1
openSUSE:Leap 15.4	python-cryptography	before 3.3.2-150400.16.3.1	3.3.2-150400.16.3.1
openSUSE:Leap 15.4	python-cryptography-vectors	before 3.3.2-150400.7.3.1	3.3.2-150400.7.3.1
openSUSE:Leap 15.4	python-humanfriendly	before 10.0-150100.6.3.3	10.0-150100.6.3.3
openSUSE:Leap 15.4	python-hyperlink	before 17.2.1-150000.3.4.1	17.2.1-150000.3.4.1
openSUSE:Leap 15.4	python-jsondiff	before 1.3.0-150100.3.6.3	1.3.0-150100.3.6.3
openSUSE:Leap 15.4	python-knack	before 0.9.0-150100.3.7.3	0.9.0-150100.3.7.3
openSUSE:Leap 15.4	python-websocket-client	before 1.3.2-150100.6.7.3	1.3.2-150100.6.7.3
openSUSE:Leap 15.4	python-zope.interface	before 4.4.2-150000.3.4.1	4.4.2-150000.3.4.1
openSUSE:Tumbleweed	python-cryptography	before 42.0.5-1.1	42.0.5-1.1
openSUSE:Tumbleweed	python-cryptography	before 50.0.0-1.1	50.0.0-1.1
openSUSE:Tumbleweed	python-cryptography	before 3.3.2-2.4	3.3.2-2.4
PyPI	cryptography	before 3.2.1	3.2.1
PyPI	cryptography	before 3.2	3.2
Red Hat:enterprise_linux:8::baseos	python-cryptography	before 0:3.2.1-4.el8	0:3.2.1-4.el8
Red Hat:enterprise_linux:8::baseos	python-cryptography-debugsource	before 0:3.2.1-4.el8	0:3.2.1-4.el8
Red Hat:enterprise_linux:8::baseos	python3-cryptography	before 0:3.2.1-4.el8	0:3.2.1-4.el8
Red Hat:enterprise_linux:8::baseos	python3-cryptography-debuginfo	before 0:3.2.1-4.el8	0:3.2.1-4.el8
Red Hat:rhel_software_collections:3::el7	rh-python38-babel	before 0:2.7.0-12.el7	0:2.7.0-12.el7
Red Hat:rhel_software_collections:3::el7	rh-python38-python	before 0:3.8.11-2.el7	0:3.8.11-2.el7

+96

Same product

cryptography.io: all records

Other highest-scoring records for the same primary product.

CVE-2020-36242In the cryptography package before 3.3.2 for Python, certain sequences of update calls to symmetrically encrypt multi-GB values could…
38Monitor
CVE-2026-26007cryptography Subgroup Attack Due to Missing Subgroup Validation for SECT Curves
32Monitor
CVE-2016-9243HKDF in cryptography before 1.5.2 returns an empty byte-string if used with a length less than algorithm.digest_size.
31Monitor

Published before and after this one in the same product

Later →CVE-2023-23931Feb 7, 2023 · Cipher.update_into can corrupt memory in pyca cryptography
26Monitor
Later →CVE-2023-38325Jul 14, 2023 · The cryptography package before 41.0.2 for Python mishandles SSH certificates that have critical options.
30Monitor
Later →CVE-2023-49083Nov 29, 2023 · cryptography vulnerable to NULL-dereference when loading PKCS7 certificates
30Monitor

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:py3-cryptography	3.2.1-r0 · Alpine:v3.13	Package registry (OSV)
debian:python-cryptography	3.2.1-1 · Debian:12	Package registry (OSV)
opensuse:azure-cli-core	2.17.1-150100.6.18.1 · openSUSE:Leap 15.4	Package registry (OSV)
opensuse:python-constantly	15.1.0-150000.3.4.1 · openSUSE:Leap 15.4	Package registry (OSV)
opensuse:python-cryptography	3.3.2-150400.16.3.1 · openSUSE:Leap 15.4	Package registry (OSV)
opensuse:python-cryptography-vectors	3.3.2-150400.7.3.1 · openSUSE:Leap 15.4	Package registry (OSV)
opensuse:python-humanfriendly	10.0-150100.6.3.3 · openSUSE:Leap 15.4	Package registry (OSV)
opensuse:python-hyperlink	17.2.1-150000.3.4.1 · openSUSE:Leap 15.4	Package registry (OSV)
opensuse:python-jsondiff	1.3.0-150100.3.6.3 · openSUSE:Leap 15.4	Package registry (OSV)
opensuse:python-knack	0.9.0-150100.3.7.3 · openSUSE:Leap 15.4	Package registry (OSV)
opensuse:python-websocket-client	1.3.2-150100.6.7.3 · openSUSE:Leap 15.4	Package registry (OSV)
opensuse:python-zope.interface	4.4.2-150000.3.4.1 · openSUSE:Leap 15.4	Package registry (OSV)
PyPI:cryptography	3.2	Package registry (OSV)
PyPI:cryptography	3.2.1	Package registry (OSV)
red hat:python-cryptography	0:3.2.1-4.el8 · Red Hat:enterprise_linux:8::baseos	Package registry (OSV)
red hat:python-cryptography-debugsource	0:3.2.1-4.el8 · Red Hat:enterprise_linux:8::baseos	Package registry (OSV)
red hat:python3-cryptography	0:3.2.1-4.el8 · Red Hat:enterprise_linux:8::baseos	Package registry (OSV)
red hat:python3-cryptography-debuginfo	0:3.2.1-4.el8 · Red Hat:enterprise_linux:8::baseos	Package registry (OSV)
red hat:redhat-virtualization-host	0:4.4.6-20210527.3.el8_4 · Red Hat:rhev_hypervisor:4.4::el8	Package registry (OSV)
red hat:redhat-virtualization-host-image-update	0:4.4.6-20210527.3.el8_4 · Red Hat:rhev_hypervisor:4.4::el8	Package registry (OSV)
red hat:rh-python38-babel	0:2.7.0-12.el7 · Red Hat:rhel_software_collections:3::el7	Package registry (OSV)
red hat:rh-python38-python	0:3.8.11-2.el7 · Red Hat:rhel_software_collections:3::el7	Package registry (OSV)
red hat:rh-python38-python-babel	0:2.7.0-12.el7 · Red Hat:rhel_software_collections:3::el7	Package registry (OSV)
red hat:rh-python38-python-cryptography	0:2.8-5.el7 · Red Hat:rhel_software_collections:3::el7	Package registry (OSV)
red hat:rh-python38-python-cryptography-debuginfo	0:2.8-5.el7 · Red Hat:rhel_software_collections:3::el7	Package registry (OSV)
red hat:rh-python38-python-debug	0:3.8.11-2.el7 · Red Hat:rhel_software_collections:3::el7	Package registry (OSV)
rocky linux:python-cryptography	0:3.2.1-4.el8 · Rocky Linux:8	Package registry (OSV)
suse:azure-cli-core	2.17.1-150100.6.18.1 · SUSE:Linux Enterprise Module for Public Cloud 15 SP1	Package registry (OSV)
suse:grpc	1.25.0-150100.3.3.3 · SUSE:Linux Enterprise Module for Public Cloud 15 SP1	Package registry (OSV)
suse:protobuf	3.9.2-150100.8.3.3 · SUSE:Linux Enterprise Installer Updates 15 SP1	Package registry (OSV)

+19

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

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.