CVE-2020-14967Public exploitNetwork attack vector

Modified ciphertext acceptance via unchecked leading zeros

Published Jun 22, 2020 · Updated Aug 4, 2024

Improper ciphertext validation in jsrsasign before 8.0.18 allows attackers to submit modified RSA ciphertexts that decrypt without error. The RSAES-PKCS1-v1_5 and RSA-OAEP decryption paths convert encrypted messages to BigInteger values without rejecting unnecessary leading zero bytes. Affected applications must invoke either RSA decryption mode on attacker-controlled ciphertext; the upstream advisory rates message-forgery and memory-corruption risks as low.

CVSS severity9.8
Critical
EPSS probability2.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper ciphertext validation in jsrsasign before 8.0.18 allows attackers to submit modified RSA ciphertexts that decrypt without error. The RSAES-PKCS1-v1_5 and RSA-OAEP decryption paths convert encrypted messages to BigInteger values without rejecting unnecessary leading zero bytes. Affected applications must invoke either RSA decryption mode on attacker-controlled ciphertext; the upstream advisory rates message-forgery and memory-corruption risks as low.

The record

CVE
CVE-2020-14967
Published
Jun 22, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-119
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 22, 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

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NVDAV:N/AC:L/Au:N/C:P/I:P/A:P

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 exploitPublished

Weakness, pattern, technique

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer

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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