CVE-2021-22923Network attack vector

Credential disclosure via Metalink credential reuse

Published Aug 5, 2021 · Updated Nov 19, 2024

Credential exposure in curl 7.27.0 through 7.77.0 allows remote attackers to obtain credentials via servers listed in a Metalink file. The Metalink transfer logic reuses the username and password supplied for the XML request when contacting every download server named by that file. Exploitation requires a user to invoke the curl tool with Metalink and credentials; libcurl is unaffected, and the consequence is disclosure to a listed server.

CVSS severity5.3
Medium
EPSS probability1.89%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Credential exposure in curl 7.27.0 through 7.77.0 allows remote attackers to obtain credentials via servers listed in a Metalink file. The Metalink transfer logic reuses the username and password supplied for the XML request when contacting every download server named by that file. Exploitation requires a user to invoke the curl tool with Metalink and credentials; libcurl is unaffected, and the consequence is disclosure to a listed server.

The record

CVE
CVE-2021-22923
Published
Aug 5, 2021
Updated
Nov 19, 2024
Vendor
curl
Product
curl
Classifications
CWE-319, CWE-522
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 5, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 19, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=curl 7.27.0 to and including 7.77.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

curl · curlversion=curl 7.27.0 to and including 7.77.0

Published CVSS scores

5.3NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N
2.6NIST NVDAV:N/AC:H/Au:N/C:P/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 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-319Cleartext Transmission of Sensitive Information
CWE-522Insufficiently Protected Credentials

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo