CVE-2026-73476: External Authentication - Moderately critical - Access bypass - SA-CONTRIB-2026-098

Recommended actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Fix not verified

What, why and how

Improper Handling of Case Sensitivity vulnerability in Drupal External Authentication allows Privilege Escalation. This issue affects External Authentication versions: from 0.0.0 to 2.0.13.

What

Improper Handling of Case Sensitivity vulnerability in Drupal External Authentication allows Privilege Escalation. This issue affects External Authentication versions: from 0.0.0 to 2.0.13.

Why

The product does not properly account for differences in case sensitivity when accessing or determining the properties of a resource, leading to inconsistent results.

How

An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may gain additional privileges.

What

Improper Handling of Case Sensitivity vulnerability in Drupal External Authentication allows Privilege Escalation. This issue affects External Authentication versions: from 0.0.0 to 2.0.13.

Why

The product does not properly account for differences in case sensitivity when accessing or determining the properties of a resource, leading to inconsistent results.

How

An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may gain additional privileges.

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 Handling of Case Sensitivity → gain additional privileges
Attack surface: Network
Privileges required: Low: a basic authenticated account is required
User interaction: None
Attack complexity: Low: no specialised conditions are recorded
Security boundary: Unchanged: impact remains within the vulnerable component's security authority
Weakness ? CWE means Common Weakness Enumeration: a standard category for the underlying weakness.: CWE-178 ↗
CWE-178: Improper Handling of Case Sensitivity. The product does not properly account for differences in case sensitivity when accessing or determining the properties of a resource, leading to inconsistent results.
CVSS vector ? CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Common Vulnerability Scoring System 3.1: 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.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CLowConfidentiality impact: A successful attack can cause a limited loss.ILowIntegrity impact: A successful attack can cause a limited loss.ANoneAvailability impact: 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.

NetworkPrivilege escalationCWE-178

Official authority intelligence

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

ENISA EUVD · EUVD-2026-69990Official EUVD mapping

Improper Handling of Case Sensitivity vulnerability in Drupal External Authentication allows Privilege Escalation. This issue affects External Authentication versions: from 0.0.0 to 2.0.13.

Official EUVD record ↗

BSI · German · WID-SEC-2026-2826Drupal Module: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Drupal ausnutzen, um Informationen offenzulegen, Daten zu manipulieren und Sicherheitsmaßnahmen zu umgehen.

Official advisory ↗

Cyber Security Agency of Singapore · English · CSA-SB-20260909Security Bulletin 9 Sep 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 9 Sep 2026, published on 9 September 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗

JVN iPedia · Japanese · JVNDB-2026-033729External Authentication ProjectのExternal Authenticationにおける大文字と小文字の区別の不適切な処理に関する脆弱性

Drupal External Authentication における大文字と小文字の区別を適切に処理できない脆弱性により、権限昇格が可能となります。この問題は、External Authentication のバージョン 0.0.0 から 2.0.13 に影響を及ぼします。

Official advisory ↗

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: External Authentication: 0.0.0 < 2.0.13
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.

Evidence and provenance

Published 2 Sept 2026 · Last source change 2 Sept 2026, 18:38 UTC · CWE-178 · Improper Handling of Case Sensitivity

CVE recordCVE.org · 5.2

CVSS sourceCISA ADP

EPSS source

The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.

FIRST · tracked since 2026-09-03

European sourceENISA EUVD · EUVD-2026-69990

Product sourceCNA

Remediation sourceCVE/CNA references

CWE sourceCNA

NVD statusNVD enriched

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

Material change intelligence

What changed after publication

View recent updates ↗

2 Sep 2026, 20:03 UTC
ENISA EUVD mappingEUVD-2026-69990 was added to the official ENISA EUVD mapping for this CVE.
Before
not recorded
After
{"euvdId":"EUVD-2026-69990"}
ENISA EUVD ↗
2 Sep 2026, 18:38 UTC
Vendor guidanceAuthoritative vendor guidance changed: added vendor advisory: drupal.org/sa-contrib-2026-098.
Before
no authoritative guidance recorded
After
vendor advisory: drupal.org/sa-contrib-2026-098
mlhess@drupal.org ↗
2 Sep 2026, 18:38 UTC
Affected versionsThe structured affected or fixed version information changed.
Before
0.0.0 < 2.0.13 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
After
External Authentication: 0.0.0 < 2.0.13 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
CNA ↗
2 Sep 2026, 18:38 UTC
SeveritySeverity changed from Unknown to Medium.
Before
Unknown
After
Medium
CISA ADP ↗
2 Sep 2026, 18:38 UTC
CVSS scoreCVSS score changed from not recorded to 5.4 (CVSS 3.1 · CISA ADP · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N).
Before
not recorded
After
5.4 (CVSS 3.1 · CISA ADP · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N)
CISA ADP ↗
2 Sep 2026, 12:32 UTC
Catalogue recordCVE added to the BlackTree catalogue.
CNA ↗

2026-09-02CVE published

ENISA EUVD · EUVD-2026-69990↗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.

External Authentication - Moderately critical - Access bypass - SA-CONTRIB-2026-098

Published severity in operational context

Evidence used

Compensating controls

Verification

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

ENISA European Vulnerability Database

EUVD-2026-69990

What, why and how

Exploit reality and attack path

Official authority intelligence

Patch and workaround

Evidence and provenance

What changed after publication