High Memory corruption exploit reference

CVE-2017-9047 — A buffer overflow was discovered in libxml2 20904-GITv2.9.4-16-g0741801. The function...

A buffer overflow was discovered in libxml2 20904-GITv2.9.4-16-g0741801. The function xmlSnprintfElementContent in valid.c is supposed to recursively dump the element content definition into a char buffer 'buf' of size 'size'. The variable len is assigned strlen(buf). If the content->type is XML_ELEMENT_CONTENT_ELEMENT, then (i) the content->prefix is appended to buf (if it actually fits) whereupon (ii) content->name is written to the buffer. However, the check for whether the content->name actually fits also uses 'len' rather than the updated buffer length strlen(buf). This allows us to write about "size" many bytes beyond the allocated memory. This vulnerability causes programs that use libxml2, such as PHP, to crash.

Published May 18, 2017 · Updated Oct 14, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · 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 3.2% (30-day exploitation probability)+13
Technical severity (high)+6

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

3.19%

ahead of 88% of scored CVEs · Oct 14, 2026

Affects

Xmlsoft

Libxml2

CVSS base

7.5

High · 2 source(s)

Remediation

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

Documented patch — www.openwall.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 (Xmlsoft Libxml2).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
Apply the fixed version or the patch documented under Remediation.
Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Xmlsoft	Libxml2	version 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

Network

Attack complexity

Low

Privileges required

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

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
7.5	CVSS 3.0	High	3.9	3.6	nvd@nist.gov via NIST National Vulnerability Database
7.5	CVSS 3.0	High	—	—	GitHub, Inc. via GitHub Security Advisories
5.0	CVSS 2.0	Medium	10.0	2.9	nvd@nist.gov via NIST National Vulnerability Database

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-119 · Buffer Errors (Improper Restriction of Operations within Memory Bounds)

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 3.19%

Detection

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

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.

web/proxy/WAF logsnetwork IDS/IPSendpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

2026
Record published
Oct 14, 2026
Fix documented
Oct 14, 2026 · NIST National Vulnerability Database
Affected products added · xmlsoft/libxml2
Oct 14, 2026 · NIST National Vulnerability Database
CVSS changed · 7.5
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
2017
CVE published
May 18, 2017 · mitre

Source activity

Repeated readings are counted rather than listed.

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

References

11 on the record

www.openwall.com/lists/oss-security/2017/05/15/1
Exploit, Mailing List, Patch, Third Party Advisory, x_refsource_MISC, NIST National Vulnerability Database
lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b
mailing-list, x_refsource_MLIST, NIST National Vulnerability Database
lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4
GitHub Security Advisories
cert-portal.siemens.com/productcert/html/ssa-398330.html
NIST National Vulnerability Database
nvd.nist.gov/vuln/detail/CVE-2017-9047
GitHub Security Advisories
security.gentoo.org/glsa/201711-01
vendor-advisory, x_refsource_GENTOO, NIST National Vulnerability Database
lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b
GitHub Security Advisories
github.com/advisories/GHSA-m5m9-w72w-8c23
GitHub Security Advisories
lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4
mailing-list, x_refsource_MLIST, NIST National Vulnerability Database
www.debian.org/security/2017/dsa-3952
vendor-advisory, x_refsource_DEBIAN, NIST National Vulnerability Database
www.securityfocus.com/bid/98599
Third Party Advisory, VDB Entry, vdb-entry, x_refsource_BID, NIST National Vulnerability Database

Elsewhere on this site

Xmlsoft
every CVE for this vendor

Memory corruption
same class

CWE-119
other pages naming this weakness

Related CVEs (same products)

High CVE-2026-11979 Stack-Based Buffer Overflow in libxml2 Jun 29, 2026
Critical CVE-2026-6653 libxml2 Use-After-Free in xmlParseInternalSubset Causing Denial of Service Jun 22, 2026
High CVE-2026-6732 Libxml2: libxml2: denial of service via crafted xsd-validated document Apr 23, 2026
Low CVE-2026-0989 Libxml2: unbounded relaxng include recursion leading to stack overflow Jan 15, 2026
Low CVE-2026-0992 Libxml2: libxml2: denial of service via crafted xml catalogs Jan 15, 2026
Medium CVE-2026-0990 Libxml2: libxml2: denial of service via uncontrolled recursion in xml catalog processing Jan 15, 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 CISA SSVC assessment.
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-2017-9047 is "A buffer overflow was discovered in libxml2 20904-GITv2.9.4-16-g0741801. The function...", rated High. It affects Libxml2 (Xmlsoft); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.5 describes technical severity. EPSS 3.19% 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.

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