When curl is instructed to download content using the metalink feature, thecontents is verified against a hash provided in the metalink XML

Summary

When curl is instructed to download content using the metalink feature, thecontents is verified against a hash provided in the metalink XML file.The metalink XML file points out to the client how to get the same contentfrom a set of different URLs, potentially hosted by different servers and theclient can then download the file from one or several of them. In a serial orparallel manner.If one of the servers hosting the contents has been breached and the contentsof the specific file on that server is replaced with a modified payload, curlshould detect this when the hash of the file mismatches after a completeddownload. It should remove the contents and instead try getting the contentsfrom another URL. This is not done, and instead such a hash mismatch is onlymentioned in text and the potentially malicious content is kept in the file ondisk.

Timeline

1. Aug 5, 2021, 12:00 AM UTCCVE published
2. Apr 16, 2026, 2:09 PM UTCCISA SSVC assessment

   Exploitation: poc · Automatable: no · Technical impact: partial

3. Oct 14, 2026, 10:37 AM UTCRecord last updated

Affected versions

• n/a https://github.com/curl/curl

  curl 7.27.0 to and including 7.77.0

References 10