CVE-2021-3642Network attack vector

Authentication information disclosure via early-exit SCRAM comparisons

Published Aug 5, 2021 · Updated Aug 3, 2024

Timing side channel in Red Hat WildFly Elytron allows remote authenticated users to disclose SCRAM authentication information. ScramServer uses early-exit comparisons for the message nonce and recovered client key, so response times expose the first mismatching byte. Exposure requires SCRAM to be enabled and affects releases before 1.10.14.Final, 1.11.0 through 1.15.4.Final, and 1.16.0.Final; no integrity or availability impact is reported.

CVSS severity3.1
Low
EPSS probability0.85%
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 Red Hat WildFly Elytron allows remote authenticated users to disclose SCRAM authentication information. ScramServer uses early-exit comparisons for the message nonce and recovered client key, so response times expose the first mismatching byte. Exposure requires SCRAM to be enabled and affects releases before 1.10.14.Final, 1.11.0 through 1.15.4.Final, and 1.16.0.Final; no integrity or availability impact is reported.

The record

CVE
CVE-2021-3642
Published
Aug 5, 2021
Updated
Aug 3, 2024
Vendor
Red Hat
Product
WildFly Elytron
Classifications
CWE-203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 5, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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=Wildfly Elytron 1.10.14.Final, Wildfly Elytron 1.15.5.Final, Wildfly Elytron 1.16.1.Final

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Red Hat · WildFly Elytronversion=Wildfly Elytron 1.10.14.Final, Wildfly Elytron 1.15.5.Final, Wildfly Elytron 1.16.1.Final

Published CVSS scores

3.1Red HatCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N
5.3NIST NVDCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-203Observable Discrepancy

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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