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 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.

Published: 2016-05-05 Last update: 2026-05-06 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2016-2167 is rated Moderate Risk (53.8/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.97%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2016-2167

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-02 1.20% 0.97% -0.23%
2 2026-02-18 1.60% 1.20% -0.40%
3 2026-01-21 — 1.60% —

Full EPSS history (18 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2016-2167

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.8 3.0 MEDIUM
CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 1.6 5.2 [email protected]
4.9 2.0 MEDIUM
AV:N/AC:M/Au:S/C:P/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 6.8 4.9 [email protected]

Weakness enumeration for CVE-2016-2167

OS Trackers for CVE-2016-2167

vendor priority summary link
debian not yet assigned CVE-2016-2167 not yet assigned priority: Debian including 1 source packages (subversion), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2016-2167
gentoo normal CVE-2016-2167: 1 GLSA(s) (201610-05), 2 atom(s) (dev-vcs/subversion, net-libs/serf); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2016-2167
redhat low — https://access.redhat.com/security/cve/CVE-2016-2167
suse low CVE-2016-2167 severity low: SUSE including 85 source package names (libsvn_auth_gnome_keyring-1-0-1.10.6-1.12, libsvn_auth_gnome_keyring-1-0-1.8.10-21.1, …), 126 product×package rows across 31 product lines (SUSE Linux Enterprise Module for Basesystem 15, SUSE Linux Enterprise Module for Basesystem 15 SP1, … (31 product lines)): Fixed 126. https://www.suse.com/security/cve/CVE-2016-2167/
ubuntu low CVE-2016-2167 low priority: Ubuntu including 1 source packages (subversion), 8 status rows across 8 suites (artful, precise, trusty, upstream, wily, xenial, yakkety, zesty): not-affected 3, released 3, ignored 2. https://ubuntu.com/security/CVE-2016-2167

Affected software / configurations for CVE-2016-2167

Vendor Product Version Raw CPE
apache subversion <= 1.8.15 cpe:2.3:a:apache:subversion:*:*:*:*:*:*:*:*
apache subversion 1.9.0 cpe:2.3:a:apache:subversion:1.9.0:*:*:*:*:*:*:*
apache subversion 1.9.1 cpe:2.3:a:apache:subversion:1.9.1:*:*:*:*:*:*:*
apache subversion 1.9.2 cpe:2.3:a:apache:subversion:1.9.2:*:*:*:*:*:*:*
apache subversion 1.9.3 cpe:2.3:a:apache:subversion:1.9.3:*:*:*:*:*:*:*

References for CVE-2016-2167

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