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Full vulnerability report · 2026
CVE-2026-113582High confidence

Apache Abdera: XML external entity expansion in Atom document parsing

Apache Software Foundation · Apache Abdera

8.7HighCVSS 4.0
Recommended action
Within 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Fix not verified
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:High, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 0.46% for the current model date.

Compensating controls

  • Restrict the affected network interface to trusted sources where business-safe.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs Apache Software Foundation Apache Abdera and falls inside the recorded affected range.
  2. Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 30 daysRemediation target: Within 180 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-108166

No EUVD known-exploited evidence

UNSUPPORTED WHEN ASSIGNED Improper restriction of XML external entity references in Apache Abdera allows an attacker to access sensitive data or make server-side requests when an application parses attacker-controlled XML with Abdera. This issue affects Apache Abdera: all versions. Apache Abdera is retired and no longer supported, so we do not plan to release a version that fixes this issue. Users are recommended to migrate to a maintained alternative. Applications that cannot migrate should ensure that untrusted XML cannot reach the affected Abdera parser or JDBC adapter parsing paths. Actively maintained downstream products may still be impacted if they include an affected Abdera artifact. NOTE: This vulnerability only affects products that are no longer supported by the maintainer.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
8.7 · CVSS 4.0
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Fix not verified
01

What, why and how

UNSUPPORTED WHEN ASSIGNED Improper restriction of XML external entity references in Apache Abdera allows an attacker to access sensitive data or make server-side requests when an application parses attacker-controlled XML with Abdera. This issue affects Apache Abdera: all versions. Apache Abdera is retired and no longer supported, so we do not plan to release a version that fixes this issue. Users are recommended to migrate to a maintained alternative. Applications that cannot migrate should ensure that untrusted XML cannot reach the affected Abdera parser or JDBC adapter parsing paths. Actively maintained downstream products may still be impacted if they include an affected Abdera artifact. NOTE: This vulnerability only affects products that are no longer supported by the maintainer.

What

UNSUPPORTED WHEN ASSIGNED Improper restriction of XML external entity references in Apache Abdera allows an attacker to access sensitive data or make server-side requests when an application parses attacker-controlled XML with Abdera. This issue affects Apache Abdera: all versions. Apache Abdera is retired and no longer supported, so we do not plan to release a version that fixes this issue. Users are recommended to migrate to a maintained alternative. Applications that cannot migrate should ensure that untrusted XML cannot reach the affected Abdera parser or JDBC adapter parsing paths. Actively maintained downstream products may still be impacted if they include an affected Abdera artifact. NOTE: This vulnerability only affects products that are no longer supported by the maintainer.

Why

The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

UNSUPPORTED WHEN ASSIGNED Improper restriction of XML external entity references in Apache Abdera allows an attacker to access sensitive data or make server-side requests when an application parses attacker-controlled XML with Abdera. This issue affects Apache Abdera: all versions. Apache Abdera is retired and no longer supported, so we do not plan to release a version that fixes this issue. Users are recommended to migrate to a maintained alternative. Applications that cannot migrate should ensure that untrusted XML cannot reach the affected Abdera parser or JDBC adapter parsing paths. Actively maintained downstream products may still be impacted if they include an affected Abdera artifact. NOTE: This vulnerability only affects products that are no longer supported by the maintainer.

Why

The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Improper Restriction of XML External Entity Reference → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Not a CVSS 4.0 base metric
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-611 ↗

CWE-611: Improper Restriction of XML External Entity Reference. The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Common Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.ATNoneAttack requirements: No additional deployment or execution condition is required.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.VCHighVulnerable-system confidentiality: A successful attack can cause a major loss.VINoneVulnerable-system integrity: No direct loss is represented by this metric.VANoneVulnerable-system availability: No direct loss is represented by this metric.SCNoneSubsequent-system confidentiality: No direct loss is represented by this metric.SINoneSubsequent-system integrity: No direct loss is represented by this metric.SANoneSubsequent-system availability: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-611
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-108166Official EUVD mapping

UNSUPPORTED WHEN ASSIGNED Improper restriction of XML external entity references in Apache Abdera allows an attacker to access sensitive data or make server-side requests when an application parses attacker-controlled XML with Abdera. This issue affects Apache Abdera: all versions. Apache Abdera is retired and no longer supported, so we do not plan to release a version that fixes this issue. Users are recommended to migrate to a maintained alternative. Applications that cannot migrate should ensure that untrusted XML cannot reach the affected Abdera parser or JDBC adapter parsing paths. Actively maintained downstream products may still be impacted if they include an affected Abdera artifact. NOTE: This vulnerability only affects products that are no longer supported by the maintainer.

Official EUVD record ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Fix not verified
Affected
Apache Abdera: ≤ *, cb5a3646fc8b2a620dba5bdde3a6b7a3753b1be2 ≤ *
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 22 Oct 2026 · Last source change 22 Oct 2026, 20:08 UTC · CWE-611 · Improper Restriction of XML External Entity Reference

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-10-23
European sourceENISA EUVD · EUVD-2026-108166
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD not scheduled

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. ENISA EUVD mappingEUVD-2026-108166 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2026-108166"}
    ENISA EUVD ↗
  2. Catalogue recordCVE added to the BlackTree catalogue.
    Official European vulnerability authority ↗
  3. Vendor guidanceAuthoritative vendor guidance changed: removed vendor advisory: lists.apache.org/j32tow7bhfnn2p0obsqy1mhg1qs7hq91.
    Before
    vendor advisory: lists.apache.org/j32tow7bhfnn2p0obsqy1mhg1qs7hq91
    After
    no authoritative guidance recorded
    CNA ↗
  4. Vendor guidanceAuthoritative vendor guidance changed: added vendor advisory: lists.apache.org/j32tow7bhfnn2p0obsqy1mhg1qs7hq91; removed remediation: euvd.enisa.europa.eu/EUVD-2026-108166.
    Before
    remediation: euvd.enisa.europa.eu/EUVD-2026-108166
    After
    vendor advisory: lists.apache.org/j32tow7bhfnn2p0obsqy1mhg1qs7hq91
    lists.apache.org ↗
  5. Affected versionsThe structured affected or fixed version information changed.
    Before
    Apache Software Foundation Apache Abdera cb5a3646fc8b2a620dba5bdde3a6b7a3753b1be2 ≤*; Apache Software Foundation Apache Abdera 0 ≤* · Fixed: No fixed version is explicitly recorded in the available ENISA EUVD evidence.
    After
    Apache Abdera: ≤ *, cb5a3646fc8b2a620dba5bdde3a6b7a3753b1be2 ≤ * · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    CNA ↗
  6. CVSS scoreCVSS scoring authority changed from Other authority to CNA; the displayed base score remained 8.7.
    Before
    8.7 (CVSS 4.0 · Other authority · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N)
    After
    8.7 (CVSS 4.0 · CNA · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N)
    CNA ↗
  7. Affected versionsThe structured affected or fixed version information changed.
    Before
    ENISA EUVD does not provide a structured affected-product range for this provisional report. · Fixed: No fixed version is explicitly recorded in the available ENISA EUVD evidence.
    After
    Apache Software Foundation Apache Abdera cb5a3646fc8b2a620dba5bdde3a6b7a3753b1be2 ≤*; Apache Software Foundation Apache Abdera 0 ≤* · Fixed: No fixed version is explicitly recorded in the available ENISA EUVD evidence.
    Official European vulnerability authority ↗
  8. SeveritySeverity changed from Unknown to High.
    Before
    Unknown
    After
    High
    Other authority ↗
  9. CVSS scoreCVSS score changed from not recorded to 8.7 (CVSS 4.0 · Other authority · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N).
    Before
    not recorded
    After
    8.7 (CVSS 4.0 · Other authority · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N)
    Other authority ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
ENISA EUVD · EUVD-2026-108166↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-113582 · cve.blacktree.nl