CVE-2021-43298Network attack vector

HTTP Basic password recovery via response timing

Published Jan 25, 2022 · Updated Aug 4, 2024

Observable timing discrepancy in EmbedThis GoAhead before 5.1.4 allows remote attackers to recover an HTTP Basic password. The Basic-auth password matcher uses a non-constant-time memory comparison and imposes no rate limit, so 401 response latency reveals each matching byte. The target must expose a password-protected Basic-auth route over the network; successful recovery grants that account's access.

CVSS severity9.8
Critical
EPSS probability2.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Observable timing discrepancy in EmbedThis GoAhead before 5.1.4 allows remote attackers to recover an HTTP Basic password. The Basic-auth password matcher uses a non-constant-time memory comparison and imposes no rate limit, so 401 response latency reveals each matching byte. The target must expose a password-protected Basic-auth route over the network; successful recovery grants that account's access.

The record

CVE
CVE-2021-43298
Published
Jan 25, 2022
Updated
Aug 4, 2024
Vendor
EmbedThis
Product
GoAhead
Classifications
CWE-307, CWE-208, T1110.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 25, 2022CVE 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <5.1.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

EmbedThis · GoAheadversion=unspecified <5.1.4

Published CVSS scores

5.0NVDAV:N/AC:L/Au:N/C:P/I:N/A:N
9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-307Improper Restriction of Excessive Authentication Attempts
CWE-208Observable Timing Discrepancy
T1110.001Brute Force: Password Guessing

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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