This High severity SSRF (Server-Side Request Forgery) vulnerability was introduced in versions 9.4.12, 10.2.0, and 10.3.0 of Bitbucket Data Center.

This SSRF (Server-Side Request Forgery) vulnerability, with a CVSS Score of 8.6 and a CVSS Vector of CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N allows an unauthenticated attacker to access the content of internal network resources. When running in an environment like Amazon EC2, this flaw may be used to access a metadata resource that provides access credentials and other potentially confidential information which has high impact to confidentiality, no impact to integrity, no impact to availability, and requires no user interaction.

Atlassian recommends that Bitbucket Data Center customers upgrade to latest version, if you are unable to do so, upgrade your instance to one of the specified supported fixed versions:

• Bitbucket Data Center 9.4: Upgrade to a release greater than or equal to 9.4.21

• Bitbucket Data Center 10.2: Upgrade to a release greater than or equal to 10.2.4

• Bitbucket Data Center 10.3: Upgrade to a release greater than or equal to 10.3.1

See the release notes (https://confluence.atlassian.com/bitbucketserver/release-notes). You can download the latest version of Bitbucket Data Center from the download center (https://www.atlassian.com/software/bitbucket/download-archives).

The National Vulnerability Database provides the following description for this vulnerability: Axios is a promise based HTTP client for the browser and Node.js. Prior to 0.32.0 and 1.16.0, Axios does not normalise IPv4-mapped IPv6 addresses. When NO_PROXY lists an IPv4 address such as 127.0.0.1 or 169.254.169.254, a request URL using the IPv4-mapped IPv6 form (::ffff:7f00:1, ::ffff:a9fe:a9fe) still routes through the configured proxy. Node.js resolves these addresses to the underlying IPv4 host, so the request reaches the internal service via the proxy rather than being blocked. This vulnerability is fixed in 0.32.0 and 1.16.0.