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CVE Record

CVE-2020-25658: It was found that python-rsa is vulnerable to Bleichenbacher timing attacks.

It was found that python-rsa is vulnerable to Bleichenbacher timing attacks. An attacker can use this flaw via the RSA decryption API to decrypt parts of the cipher text encrypted with RSA.

HighCVSS 7.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2020-25658 is a confidentiality flaw in the python-rsa library. A network attacker who can send data to an application’s RSA decryption function may use timing differences to recover portions of encrypted ciphertext. The business concern is exposure of secrets protected by RSA, not system takeover.

Executive priority

Treat as high priority where python-rsa decrypts externally supplied data or protects sensitive secrets. The issue is narrower than remote code execution, but successful exploitation can undermine confidentiality of RSA-protected data.

Technical view

python-rsa after version 3.0 inclusive is reported vulnerable to Bleichenbacher timing attacks through its RSA decryption API. The CVSS 3.1 score is 7.5, network exploitable, low complexity, no privileges, no user interaction, with high confidentiality impact only.

Likely exposure

Exposure is most likely in Python services or tools that use python-rsa to decrypt attacker-controlled RSA ciphertext, especially over a network API. Applications that do not use python-rsa, or only use it away from untrusted inputs, are less likely exposed.

Exploitation context

The source bundle does not show CISA KEV listing or public evidence of active exploitation. The attack class is practical when an attacker can repeatedly interact with a vulnerable RSA decryption path and observe timing behavior.

Researcher notes

Evidence identifies CWE-385 and a Bleichenbacher-style timing side channel. The supplied sources do not name a specific upstream fixed version, so remediation validation should be anchored to python-rsa, Red Hat, Fedora, or distribution advisories rather than assumptions.

Mitigation direction

  • Inventory applications and dependencies for python-rsa usage.
  • Check python-rsa and OS vendor guidance for fixed package versions.
  • Prioritize services exposing RSA decryption to untrusted network input.
  • Reduce or remove vulnerable RSA decryption paths where feasible.
  • Apply Fedora or distribution security updates where applicable.

Validation and detection

  • Confirm installed python-rsa versions in application dependency manifests and runtime environments.
  • Identify code paths calling the python-rsa RSA decryption API.
  • Determine whether those paths accept attacker-controlled ciphertext.
  • Review vendor advisories for package status and remediation details.
  • Check whether affected services are internet-facing or internally reachable.
Prepared
Confidence
medium
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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ATT&CK lookup starting points

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cwe · low confidence lookup

CWE-385: Exact CWE lookup

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cve · low confidence lookup

CVE-2020-25658 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.5 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
6Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N3.93.6Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

7.5High
CVSS 3.1 vector shape for CVE-2020-25658Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Sybren A. Stüvelpython-rsaafter 3.0 (inclusive)Listed
Weakness

CWE details

CWE-385

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.