CVE Intelligence
High

CVE-2026-108039 — Apache CXF: Prevent unbounded XML document size in StaxUtils by adding default element and character limits

By default, StaxUtils placed no limit on the total number of elements or the total number of characters in an XML document. A very large request could therefore use a lot of memory and CPU during parsing, especially where CXF builds a DOM from the input (for example SAAJ or WS-Security), and could cause a denial of service when no request size limit was configured. Both limits now have defaults: the maximum element count is 100 × maxChildElements (5,000,000 by default), and the maximum document size is 256M characters. Applications that process larger documents can raise the limits with the org.apache.cxf.stax.maxElementCount and org.apache.cxf.stax.maxXMLCharacters properties. Users are recommended to upgrade to versions 4.2.4 or 4.1.9 or 3.6.13, which fix this issue.

Published Oct 9, 2026 · Updated Oct 16, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: apache

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 0.3% (30-day exploitation probability)+4
  • Technical severity (high)+6
  • Automatable exploitation (SSVC)+3

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
0.33%
ahead of 24% of scored CVEs · Oct 16, 2026
Affects
Apache Software Foundation
Cxf
CVSS base
7.5
High · 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
None
none · proof-of-concept · active
Automatable
Yes
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.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

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.

  1. Identify exposed assets running the affected vendor/product/version combinations (Apache Software Foundation Cxf).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  4. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Apache Software Foundation Cxf ≥ 4.2.0 and < 4.2.4≥ 4.0.0 and < 4.1.9< 3.6.13 Vulnerable CVE Program (cve.org) e CISA ADP
Apache Software Foundation Cxf < 3.6.13≥ 4.0.0 and < 4.1.9≥ 4.2.0 and < 4.2.4 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.

ScoreVersionSeverityExpl.ImpactScored by
7.5 CVSS 3.1 High 3.9 3.6 134c704f-9b21-4f2e-91b3-4a467353bcc0 via NIST National Vulnerability Database
7.5 CVSS 3.1 High — — GitHub, Inc. via GitHub Security Advisories
7.5 CVSS 3.1 High — — CISA-ADP via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (score shown at the top: 134c704f-9b21-4f2e-91b3-4a467353bcc0)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-776

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 16, 2026 · 4 reading(s) · max 0.33%

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).
web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · apache/cxf
    Oct 16, 2026 · NIST National Vulnerability Database
  • Source status changed · Undergoing Analysis → Analyzed
    Oct 16, 2026 · NIST National Vulnerability Database
  • Affected products removed · 3
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • Affected products added · apache software foundation/apache cxf
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • CVSS changed · 7.5
    Oct 15, 2026 · NIST National Vulnerability Database
  • Record published
    Oct 13, 2026
  • Affected products added · apache software foundation/apache cxf
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Source status changed · → Undergoing Analysis
    Oct 13, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVE published
    Oct 9, 2026 · apache

Source activity

Repeated readings are counted rather than listed.

  • 1× References added · Oct 15, 2026 – Oct 15, 2026
  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

4 on the record

Elsewhere on this site

Apache Software Foundation
every CVE for this vendor
CWE-776
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-97468 Apache CXF: Authentication bypass via weak cache keys for validated STS tokens 7d
  • CVE-2026-97791 Apache CXF: STSTokenValidator can accept untrusted SAML assertions because it shares validation state between requests 7d
  • CVE-2026-79650 Apache CXF: OIDC RP Open Redirect 7d
  • CVE-2026-86463 Apache CXF: FIQL Query Parser Denial of Service 7d
  • CVE-2026-73179 Apache CXF: JPA authorization-code consume is non-atomic 7d
  • CVE-2026-71575 Apache CXF: Inoperative max_age authentication-freshness check in OidcClientCodeRequestFilter 7d

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 fixed version, patch or mitigation documented.
  • 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-2026-108039 is "Apache CXF: Prevent unbounded XML document size in StaxUtils by adding default element and character limits", rated High. It affects Cxf (Apache Software Foundation); 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 0.33% 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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