CVE-2020-4831Public exploitNetwork attack vector

TLS traffic decryption via RSA padding oracle

Published Mar 12, 2021 · Updated Sep 17, 2024

Cryptographic weakness in IBM DataPower Gateway 10.0.0.0 through 10.0.1.0 allows remote attackers to decrypt TLS traffic. Its TLS RSA key exchange exposes a ROBOT padding oracle by producing distinguishable responses to malformed PKCS #1 v1.5 ciphertexts. Exploitation requires network access to a TLS service with a static RSA cipher suite and permits confidentiality loss without data modification.

CVSS severity5.9
Medium
EPSS probability0.77%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cryptographic weakness in IBM DataPower Gateway 10.0.0.0 through 10.0.1.0 allows remote attackers to decrypt TLS traffic. Its TLS RSA key exchange exposes a ROBOT padding oracle by producing distinguishable responses to malformed PKCS #1 v1.5 ciphertexts. Exploitation requires network access to a TLS service with a static RSA cipher suite and permits confidentiality loss without data modification.

The record

CVE
CVE-2020-4831
Published
Mar 12, 2021
Updated
Sep 17, 2024
Vendor
IBM
Product
IBM DataPower Gateway
Classifications
CWE-327, T1040
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 12, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.0.0.0
  2. Affected versionversion=10.0.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

IBM · IBM DataPower Gatewayversion=10.0.0.0; version=10.0.1.0

Published CVSS scores

5.9IBM CorporationCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
5.0NIST NVDAV:N/AC:L/Au:N/C:P/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-327Use of a Broken or Risky Cryptographic Algorithm
T1040Network Sniffing

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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