CVE-2021-22901Not scoredCWE-416

CVE-2021-22901: Haxx https://github.com/curl/curl vulnerability

Haxx · https://github.com/curl/curl

Affected: Haxx https://github.com/curl/curl · Exploitation: likely to be exploited (10% or more)

Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.

63.5%probability of exploitation in the next 30 days

99th percentile

050100

Higher than 99% of scored CVEs

Not scored yet. The CVE record carries no CVSS score.

DescriptionCVE.org

curl 7.75.0 through 7.76.1 suffers from a use-after-free vulnerability resulting in already freed memory being used when a TLS 1.3 session ticket arrives over a connection. A malicious server can use this in rare unfortunate circumstances to potentially reach remote code execution in the client. When libcurl at run-time sets up support for TLS 1.3 session tickets on a connection using OpenSSL, it stores pointers to the transfer in-memory object for later retrieval when a session ticket arrives. If the connection is used by multiple transfers (like with a reused HTTP/1.1 connection or multiplexed HTTP/2 connection) that first transfer object might be freed before the new session is established on that connection and then the function will access a memory buffer that might be freed. When using that memory, libcurl might even call a function pointer in the object, making it possible for a remote code execution if the server could somehow manage to get crafted memory content into the correct place in memory.

Affected products1

From the CVE record. A product or version that is not listed is unknown, not unaffected.

https://github.com/curl/curl7.75.0 through 7.76.1

On the Atlas

Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.

Open the Atlas

Exploitation: Likely to be exploited (10% or more). EPSS gives it a 10% or higher chance of exploitation in the next 30 days.
CISA KEV: Not listed
Public check: No public nuclei template
Weakness: Use After Free · Memory Corruption
Vendor: Haxx
Published: June 2021
Band: Likely to be exploited (10% or more), June 2021
Bounty reports: 1 disclosed on HackerOne

Disclosed bug bounty reports about CVE-2021-22901

The reports on HackerOne that name this CVE, with HackerOne's own outcome. Titles and metadata only.

Path Traversal in curl file:// Protocol Handler Allows Unauthorized File Accesscurl · 2026 · high severityN/A

CoverageNo articles yet

No CyberSIXT article names CVE-2021-22901 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.

References

1 more reference is in the CVE record.