CVE-2020-13822Public exploitNetwork attack vector

Signature malleability via permissive DER length parsing

Published Jun 4, 2020 · Updated Aug 4, 2024

Improper ECDSA signature verification in elliptic before 6.5.3 allows attackers to alter a signature without invalidating it. The _importDER path in lib/elliptic/ec/signature.js accepts noncanonical ASN.1 lengths, integer-length overflows, and unnecessary leading zero bytes. An application must rely on one canonical encoding of a valid signature; the flaw produces alternate encodings that verify for the same message and key.

CVSS severity7.7
High
EPSS probability2.63%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper ECDSA signature verification in elliptic before 6.5.3 allows attackers to alter a signature without invalidating it. The _importDER path in lib/elliptic/ec/signature.js accepts noncanonical ASN.1 lengths, integer-length overflows, and unnecessary leading zero bytes. An application must rely on one canonical encoding of a valid signature; the flaw produces alternate encodings that verify for the same message and key.

The record

CVE
CVE-2020-13822
Published
Jun 4, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 4, 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

6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
7.7NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L

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 exploitPublished

Weakness, pattern, technique

CWE-190Integer Overflow or Wraparound

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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