Medium Injection exploit reference

CVE-2016-9318 — XML External Entity (XXE) in Canonical Ubuntu Linux

libxml2 2.9.4 and earlier, as used in XMLSec 1.2.23 and earlier and other products, does not offer a flag directly indicating that the current document may be read but other files may not be opened, which makes it easier for remote attackers to conduct XML External Entity (XXE) attacks via a crafted document.

Published Nov 15, 2016 · Updated Oct 14, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: mitre

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 2.9% (30-day exploitation probability)+13
Technical severity (medium)+3
CISA SSVC: exploitation "poc"+5

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

2.94%

ahead of 87% of scored CVEs · Oct 14, 2026

Affects

Canonical

Ubuntu Linux and 1 more

CVSS base

5.5

Medium · 3 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

Proof of concept

none · proof-of-concept · active

Automatable

can an attacker script the kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

Documented patch — bugzilla.gnome.org (NIST National Vulnerability Database)
Documented patch — github.com (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Canonical Ubuntu Linux, Xmlsoft Libxml2).
Apply the fixed version or the patch documented under Remediation.
Exploitation requires user interaction: tighten email/web filtering and warn affected users.
Search available logs for exploit probes matching the vulnerability class (injection), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Canonical	Ubuntu Linux	version 12.04version 14.04version 16.04version 18.04	Vulnerable	NIST National Vulnerability Database
Xmlsoft	Libxml2	≤ 2.9.4	Vulnerable	NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Local

Attack complexity

Low

Privileges required

None

User interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
5.5	CVSS 3.1	Medium	1.8	3.6	nvd@nist.gov via NIST National Vulnerability Database
5.5	CVSS 3.1	Medium	1.8	3.6	134c704f-9b21-4f2e-91b3-4a467353bcc0 via NIST National Vulnerability Database
5.5	CVSS 3.1	Medium	—	—	CISA-ADP via CVE Program (cve.org) e CISA ADP
4.3	CVSS 2.0	Medium	8.6	2.9	nvd@nist.gov via NIST National Vulnerability Database

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-611 · XML External Entity (XXE)

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 2.94%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
Look for parameters with command/query metacharacters and unexpected child processes of the service.

endpoint telemetry (EDR)application logs

Timeline

What happened to this CVE, newest first.

2026
SSVC assessment updated
Oct 14, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 14, 2026
Fix documented
Oct 14, 2026 · NIST National Vulnerability Database
Affected products added · xmlsoft/libxml2, canonical/ubuntu linux
Oct 14, 2026 · NIST National Vulnerability Database
CVSS changed · 5.5
Oct 14, 2026 · NIST National Vulnerability Database
Source status changed · → Modified
Oct 14, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 14, 2026 · Alertas do Telegram
2016
CVE published
Nov 15, 2016 · mitre

Source activity

Repeated readings are counted rather than listed.

1× References added · Oct 14, 2026 – Oct 14, 2026
1× Official description updated · Oct 14, 2026 – Oct 14, 2026

References

8 on the record

bugzilla.gnome.org/show_bug.cgi
Issue Tracking, Patch, Third Party Advisory, VDB Entry, x_refsource_MISC, NIST National Vulnerability Database
github.com/lsh123/xmlsec/issues/43
Exploit, Patch, Third Party Advisory, x_refsource_MISC, NIST National Vulnerability Database
cert-portal.siemens.com/productcert/html/ssa-398330.html
NIST National Vulnerability Database
usn.ubuntu.com/3739-1/
Third Party Advisory, vendor-advisory, x_refsource_UBUNTU, NIST National Vulnerability Database
security.gentoo.org/glsa/201711-01
Third Party Advisory, vendor-advisory, x_refsource_GENTOO, NIST National Vulnerability Database
lists.debian.org/debian-lts-announce/2022/04/msg00004.html
mailing-list, x_refsource_MLIST, NIST National Vulnerability Database
usn.ubuntu.com/3739-2/
Third Party Advisory, vendor-advisory, x_refsource_UBUNTU, NIST National Vulnerability Database
www.securityfocus.com/bid/94347
Third Party Advisory, VDB Entry, vdb-entry, x_refsource_BID, NIST National Vulnerability Database

Elsewhere on this site

Canonical
every CVE for this vendor

Injection
same class

CWE-611
other pages naming this weakness

Related CVEs (same products)

High CVE-2026-86144 Incorrect Resource Transfer Between Spheres in Xmlsoft Libxml2 Sep 5, 2026
High CVE-2026-86142 Heap-based Buffer Overflow in Xmlsoft Libxml2 Sep 5, 2026
Low CVE-2026-86141 Unchecked Return Value in Xmlsoft Libxml2 Sep 5, 2026
High CVE-2026-86143 In xmlIO in libxml2 before 2.15.4, an inconsistency in xmlOutputWriteCallback and… Sep 5, 2026
High CVE-2026-86138 Integer Overflow or Wraparound in Xmlsoft Libxml2 Sep 5, 2026
High CVE-2026-86140 Stack-based Buffer Overflow in Xmlsoft Libxml2 Sep 5, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2016-9318 is "XML External Entity (XXE) in Canonical Ubuntu Linux", rated Medium. It affects Ubuntu Linux (Canonical); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.5 describes technical severity. EPSS 2.94% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

Comments

Moderated technical discussion. Read the community guidelines.

No comments yet.