CVE-2026-55463 / GitHub GHSA-H5M9-FPVW-QR36: Goobi viewer: WebSocket endpoints lack server-side authentication and origin validation

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

The Goobi viewer is a web application that allows digitised material to be displayed in a web browser. From version 4.11.0 to before version 26.05, several Jakarta WebSocket endpoints in goobi-viewer-core (DownloadTaskEndpoint, CampaignEndpoint, AutocompleteEndpoint, UserEndpoint) accept connections without verifying that the associated HttpSession belongs to a logged-in user, and none validate the Origin header against an allowlist. An unauthenticated attacker can therefore connect to these endpoints; through CampaignEndpoint this allows polluting the in-process crowdsourcing page-lock map and broadcasting forged lock messages, disrupting reviewers' work. This issue has been patched in version 26.05.

What

Why

A security-sensitive function is reachable without the authentication check that should protect it.

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

Why

A security-sensitive function is reachable without the authentication check that should protect it.

How

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 → Missing Authentication for Critical Function → 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: Unchanged: impact remains within the vulnerable component's security authority
Weakness ? CWE means Common Weakness Enumeration: a standard category for the underlying weakness.: CWE-306 ↗
CWE-306: Missing Authentication for Critical Function. The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.
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:N/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.PRNonePrivileges required: The attacker does not need an account or existing 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.

NetworkUnauthenticatedCWE-306

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: goobi-viewer-core: >= 4.11.0, < 26.05
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 23 Oct 2026 · Last source change 23 Oct 2026, 14:17 UTC · CWE-306 · Missing Authentication for Critical Function

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.

Unavailable

European sourceNo official EUVD mapping

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 ↗

23 Oct 2026, 14:17 UTC
Catalogue recordCVE added to the BlackTree catalogue.
CNA ↗

2026-10-23CVE published

CVE authority or vendor reference · GitHub GHSA-H5M9-FPVW-QR36↗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.

Goobi viewer: WebSocket endpoints lack server-side authentication and origin validation

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.