CVE-2016-8734

Apache Subversion's mod_dontdothat module and HTTP clients 1.4.0 through 1.8.16, and 1.9.0 through 1.9.4 are vulnerable to a denial-of-service attack caused by exponential XML entity expansion. The attack can cause the targeted process to consume an excessive amount of CPU resources or memory.

Published: 2017-10-16 Last update: 2026-05-13 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2016-8734 is rated Moderate Risk (63.9/100): CVSS Medium severity, with high exploitation likelihood (EPSS 12.88%, 94th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +8.14% over the last day, indicating growing attacker interest. High exploitation likelihood—assess exposure and prioritize 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-2016-8734

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 2026-03-04 4.74% 12.88% +8.14%
2 2026-03-01 12.88% 4.74% -8.14%
3 2026-02-04 — 12.88% —

Full EPSS history (42 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2016-8734

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.0 MEDIUM
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H 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:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
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:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 3.6 [email protected]
4.0 2.0 MEDIUM
AV:N/AC:L/Au:S/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.0 2.9 [email protected]

Weakness enumeration for CVE-2016-8734

OS Trackers for CVE-2016-8734

vendor priority summary link
debian low CVE-2016-8734 low 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-2016-8734
redhat medium — https://access.redhat.com/security/cve/CVE-2016-8734
suse low CVE-2016-8734 severity low: SUSE including 75 source package names (libsvn_auth_gnome_keyring-1-0-1.10.6-1.12, libsvn_auth_gnome_keyring-1-0-1.8.19-25.3.1, …), 104 product×package rows across 29 product lines (SUSE Linux Enterprise Module for Basesystem 15, SUSE Linux Enterprise Module for Basesystem 15 SP1, … (29 product lines)): Fixed 104. https://www.suse.com/security/cve/CVE-2016-8734/
ubuntu low CVE-2016-8734 low priority: Ubuntu including 1 source packages (subversion), 14 status rows across 14 suites (artful, bionic, cosmic, disco, eoan, focal, groovy, hirsute, precise, trusty, upstream, xenial, yakkety, zesty): not-affected 9, released 3, ignored 2. https://ubuntu.com/security/CVE-2016-8734

Affected software / configurations for CVE-2016-8734

Vendor Product Version Raw CPE
apache subversion 1.4.0 cpe:2.3:a:apache:subversion:1.4.0:*:*:*:*:*:*:*
apache subversion 1.4.1 cpe:2.3:a:apache:subversion:1.4.1:*:*:*:*:*:*:*
apache subversion 1.4.2 cpe:2.3:a:apache:subversion:1.4.2:*:*:*:*:*:*:*
apache subversion 1.4.3 cpe:2.3:a:apache:subversion:1.4.3:*:*:*:*:*:*:*
apache subversion 1.4.4 cpe:2.3:a:apache:subversion:1.4.4:*:*:*:*:*:*:*
apache subversion 1.4.5 cpe:2.3:a:apache:subversion:1.4.5:*:*:*:*:*:*:*
apache subversion 1.4.6 cpe:2.3:a:apache:subversion:1.4.6:*:*:*:*:*:*:*
apache subversion 1.5.0 cpe:2.3:a:apache:subversion:1.5.0:*:*:*:*:*:*:*
apache subversion 1.5.1 cpe:2.3:a:apache:subversion:1.5.1:*:*:*:*:*:*:*
apache subversion 1.5.2 cpe:2.3:a:apache:subversion:1.5.2:*:*:*:*:*:*:*
apache subversion 1.5.3 cpe:2.3:a:apache:subversion:1.5.3:*:*:*:*:*:*:*
apache subversion 1.5.4 cpe:2.3:a:apache:subversion:1.5.4:*:*:*:*:*:*:*
apache subversion 1.5.5 cpe:2.3:a:apache:subversion:1.5.5:*:*:*:*:*:*:*
apache subversion 1.5.6 cpe:2.3:a:apache:subversion:1.5.6:*:*:*:*:*:*:*
apache subversion 1.5.7 cpe:2.3:a:apache:subversion:1.5.7:*:*:*:*:*:*:*
apache subversion 1.5.8 cpe:2.3:a:apache:subversion:1.5.8:*:*:*:*:*:*:*
apache subversion 1.6.0 cpe:2.3:a:apache:subversion:1.6.0:*:*:*:*:*:*:*
apache subversion 1.6.1 cpe:2.3:a:apache:subversion:1.6.1:*:*:*:*:*:*:*
apache subversion 1.6.2 cpe:2.3:a:apache:subversion:1.6.2:*:*:*:*:*:*:*
apache subversion 1.6.3 cpe:2.3:a:apache:subversion:1.6.3:*:*:*:*:*:*:*
apache subversion 1.6.4 cpe:2.3:a:apache:subversion:1.6.4:*:*:*:*:*:*:*
apache subversion 1.6.5 cpe:2.3:a:apache:subversion:1.6.5:*:*:*:*:*:*:*
apache subversion 1.6.6 cpe:2.3:a:apache:subversion:1.6.6:*:*:*:*:*:*:*
apache subversion 1.6.7 cpe:2.3:a:apache:subversion:1.6.7:*:*:*:*:*:*:*
apache subversion 1.6.8 cpe:2.3:a:apache:subversion:1.6.8:*:*:*:*:*:*:*
apache subversion 1.6.9 cpe:2.3:a:apache:subversion:1.6.9:*:*:*:*:*:*:*
apache subversion 1.6.10 cpe:2.3:a:apache:subversion:1.6.10:*:*:*:*:*:*:*
apache subversion 1.6.11 cpe:2.3:a:apache:subversion:1.6.11:*:*:*:*:*:*:*
apache subversion 1.6.12 cpe:2.3:a:apache:subversion:1.6.12:*:*:*:*:*:*:*
apache subversion 1.6.13 cpe:2.3:a:apache:subversion:1.6.13:*:*:*:*:*:*:*
apache subversion 1.6.14 cpe:2.3:a:apache:subversion:1.6.14:*:*:*:*:*:*:*
apache subversion 1.6.15 cpe:2.3:a:apache:subversion:1.6.15:*:*:*:*:*:*:*
apache subversion 1.6.16 cpe:2.3:a:apache:subversion:1.6.16:*:*:*:*:*:*:*
apache subversion 1.6.17 cpe:2.3:a:apache:subversion:1.6.17:*:*:*:*:*:*:*
apache subversion 1.6.18 cpe:2.3:a:apache:subversion:1.6.18:*:*:*:*:*:*:*
apache subversion 1.6.19 cpe:2.3:a:apache:subversion:1.6.19:*:*:*:*:*:*:*
apache subversion 1.6.20 cpe:2.3:a:apache:subversion:1.6.20:*:*:*:*:*:*:*
apache subversion 1.6.21 cpe:2.3:a:apache:subversion:1.6.21:*:*:*:*:*:*:*
apache subversion 1.6.23 cpe:2.3:a:apache:subversion:1.6.23:*:*:*:*:*:*:*
apache subversion 1.7.0 cpe:2.3:a:apache:subversion:1.7.0:*:*:*:*:*:*:*
apache subversion 1.7.1 cpe:2.3:a:apache:subversion:1.7.1:*:*:*:*:*:*:*
apache subversion 1.7.2 cpe:2.3:a:apache:subversion:1.7.2:*:*:*:*:*:*:*
apache subversion 1.7.3 cpe:2.3:a:apache:subversion:1.7.3:*:*:*:*:*:*:*
apache subversion 1.7.4 cpe:2.3:a:apache:subversion:1.7.4:*:*:*:*:*:*:*
apache subversion 1.7.5 cpe:2.3:a:apache:subversion:1.7.5:*:*:*:*:*:*:*
apache subversion 1.7.6 cpe:2.3:a:apache:subversion:1.7.6:*:*:*:*:*:*:*
apache subversion 1.7.7 cpe:2.3:a:apache:subversion:1.7.7:*:*:*:*:*:*:*
apache subversion 1.7.8 cpe:2.3:a:apache:subversion:1.7.8:*:*:*:*:*:*:*
apache subversion 1.7.9 cpe:2.3:a:apache:subversion:1.7.9:*:*:*:*:*:*:*
apache subversion 1.7.10 cpe:2.3:a:apache:subversion:1.7.10:*:*:*:*:*:*:*
apache subversion 1.7.11 cpe:2.3:a:apache:subversion:1.7.11:*:*:*:*:*:*:*
apache subversion 1.7.12 cpe:2.3:a:apache:subversion:1.7.12:*:*:*:*:*:*:*
apache subversion 1.7.13 cpe:2.3:a:apache:subversion:1.7.13:*:*:*:*:*:*:*
apache subversion 1.7.14 cpe:2.3:a:apache:subversion:1.7.14:*:*:*:*:*:*:*
apache subversion 1.7.15 cpe:2.3:a:apache:subversion:1.7.15:*:*:*:*:*:*:*
apache subversion 1.7.16 cpe:2.3:a:apache:subversion:1.7.16:*:*:*:*:*:*:*
apache subversion 1.7.17 cpe:2.3:a:apache:subversion:1.7.17:*:*:*:*:*:*:*
apache subversion 1.7.18 cpe:2.3:a:apache:subversion:1.7.18:*:*:*:*:*:*:*
apache subversion 1.7.19 cpe:2.3:a:apache:subversion:1.7.19:*:*:*:*:*:*:*
apache subversion 1.7.20 cpe:2.3:a:apache:subversion:1.7.20:*:*:*:*:*:*:*
apache subversion 1.8.0 cpe:2.3:a:apache:subversion:1.8.0:*:*:*:*:*:*:*
apache subversion 1.8.1 cpe:2.3:a:apache:subversion:1.8.1:*:*:*:*:*:*:*
apache subversion 1.8.2 cpe:2.3:a:apache:subversion:1.8.2:*:*:*:*:*:*:*
apache subversion 1.8.3 cpe:2.3:a:apache:subversion:1.8.3:*:*:*:*:*:*:*
apache subversion 1.8.4 cpe:2.3:a:apache:subversion:1.8.4:*:*:*:*:*:*:*
apache subversion 1.8.5 cpe:2.3:a:apache:subversion:1.8.5:*:*:*:*:*:*:*
apache subversion 1.8.6 cpe:2.3:a:apache:subversion:1.8.6:*:*:*:*:*:*:*
apache subversion 1.8.7 cpe:2.3:a:apache:subversion:1.8.7:*:*:*:*:*:*:*
apache subversion 1.8.8 cpe:2.3:a:apache:subversion:1.8.8:*:*:*:*:*:*:*
apache subversion 1.8.9 cpe:2.3:a:apache:subversion:1.8.9:*:*:*:*:*:*:*
apache subversion 1.8.10 cpe:2.3:a:apache:subversion:1.8.10:*:*:*:*:*:*:*
apache subversion 1.8.11 cpe:2.3:a:apache:subversion:1.8.11:*:*:*:*:*:*:*
apache subversion 1.8.12 cpe:2.3:a:apache:subversion:1.8.12:*:*:*:*:*:*:*
apache subversion 1.8.13 cpe:2.3:a:apache:subversion:1.8.13:*:*:*:*:*:*:*
apache subversion 1.8.14 cpe:2.3:a:apache:subversion:1.8.14:*:*:*:*:*:*:*
apache subversion 1.8.15 cpe:2.3:a:apache:subversion:1.8.15:*:*:*:*:*:*:*
apache subversion 1.8.16 cpe:2.3:a:apache:subversion:1.8.16:*:*:*:*:*:*:*
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:*:*:*:*:*:*:*

References for CVE-2016-8734

cvelogic Threat Intelligence