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CVE-2020-13757

25
FAUCET Score

CVE-2020-13757 affects Python-RSA versions before 4.1, where the library incorrectly ignores leading null bytes during ciphertext decryption. This vulnerability primarily impacts Canonical, Fedora, and Ubuntu Linux distributions utilizing Python-RSA. Rated with a CVSS score of 7.5 (High), this flaw presents a network-based attack vector with low complexity, potentially allowing attackers to infer the use of Python-RSA or trigger excessive memory allocation, though direct confidentiality or integrity impact is not specified. Currently, there is no evidence of active exploitation, nor are there publicly available exploit modules in Metasploit, Nuclei, or ExploitDB. Community discussion and media coverage for this CVE are minimal, indicating a low level of public attention.

Impacted Technologies

VendorProductVersion(s)CPE
< 4.1CPE matchmatch criteria
cpe:2.3:a:python-rsa_project:python-rsa:*:*:*:*:*:*:*:*
31CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:*
32CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
14.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:esm:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.36%
Probability of exploitation in next 30 days
EPSS Percentile
68.8%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
This CVE's current EPSS score of 0.0136 is in the 49th percentile among its peer group of 51,485 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (8)

pippatch availablevia ghsa
Product: rsaFixed in: 4.1
redhatpatch availablevia redhat_api
Product: Red Hat OpenShift Container Platform 3.11Fixed in: python-rsa-0:4.5-2.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat OpenShift Container Platform 4.5Fixed in: python-rsa-0:4.5-1.el7
View patch
redhatno patchvia redhat_api
Product: Red Hat Quay 3Fixed in: python-rsa
redhatno patchvia redhat_api
Product: Red Hat Ceph Storage 4Fixed in: python-rsa
redhatend of lifevia redhat_api
Product: Red Hat OpenStack Platform 15 (Stein)Fixed in: python-rsa
redhatend of lifevia redhat_api
Product: Red Hat OpenStack Platform 16 (Train)Fixed in: python-rsa
redhatend of lifevia redhat_api
Product: Red Hat OpenStack Platform 13 (Queens)Fixed in: python-rsa

Vendor Advisories (2)

pipGHSA-537h-rv9q-vvphhigh

Python-RSA decryption of ciphertext leads to DoS

Mar 24, 2021
redhatCVE-2020-13757Moderate

python-rsa: decryption of ciphertext leads to DoS

May 27, 2020

References

github.com / sybrenstuvel/python-rsa/issues/146
Issue TrackingThird Party Advisory
github.com / sybrenstuvel/python-rsa/issues/146
ExploitIssue TrackingThird Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/2KILTHBHNSDUCYV22ODLOKTICJJ7JQIQ
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/ZYB65VNILRBTXL6EITQTH2PZPK7I23MW
usn.ubuntu.com / 4478-1
Third Party Advisory