CVE-2020-11735Network attack vector

Private-key disclosure via variable-time modular inversion

Published Jun 25, 2020 · Updated Aug 4, 2024

Timing side channel in wolfSSL before 4.4.0 allows remote attackers to infer private-key material during ECC operations. The ecc_map path calls variable-time mp_invmod when converting private ECC results from projective to affine coordinates, causing execution time to depend on secret values. Exposure requires a fast-math build performing ECC key generation, shared-secret calculation, or signing; the reported consequence is private-key disclosure only.

CVSS severity5.3
Medium
EPSS probability1.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Timing side channel in wolfSSL before 4.4.0 allows remote attackers to infer private-key material during ECC operations. The ecc_map path calls variable-time mp_invmod when converting private ECC results from projective to affine coordinates, causing execution time to depend on secret values. Exposure requires a fast-math build performing ECC key generation, shared-secret calculation, or signing; the reported consequence is private-key disclosure only.

The record

CVE
CVE-2020-11735
Published
Jun 25, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-203, CAPEC-189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 25, 2020CVE 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

5.0NIST NVDAV:N/AC:L/Au:N/C:P/I:N/A:N
5.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-203Observable Discrepancy
CAPEC-189Black Box Reverse Engineering

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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