CVE-2020-36177Network attack vector

Memory corruption via undersized RSA-PSS buffer

Published Jan 6, 2021 · Updated Aug 4, 2024

Out-of-bounds write in wolfSSL before 4.6.0 allows remote attackers to corrupt memory through applications using RSA-PSS signing. RsaPad_PSS uses the caller's pkcsBlock as workspace even when it is shorter than the prefix, digest, and salt, so zeroing and copy operations write past the buffer. The condition requires a key that is small relative to the digest and salt; public evidence demonstrates memory corruption but no specific code-execution outcome.

CVSS severity9.8
Critical
EPSS probability3.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in wolfSSL before 4.6.0 allows remote attackers to corrupt memory through applications using RSA-PSS signing. RsaPad_PSS uses the caller's pkcsBlock as workspace even when it is shorter than the prefix, digest, and salt, so zeroing and copy operations write past the buffer. The condition requires a key that is small relative to the digest and salt; public evidence demonstrates memory corruption but no specific code-execution outcome.

The record

CVE
CVE-2020-36177
Published
Jan 6, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 6, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
10.0NVDAV:N/AC:L/Au:N/C:C/I:C/A:C

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.

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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 exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write

Public exploit references

No public exploit references are available in this record.

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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