Security readout for executives and security teams
Plain-English summary
A flaw in Hyland Alfresco’s document transformation functionality may let an unauthenticated remote attacker run code on the affected server. Successful exploitation could expose documents, alter systems, or disrupt service. Exact affected release ranges are not clearly represented in the supplied CVE data, so organizations must verify deployments against Hyland’s advisory.
Executive priority
Treat this as an immediate remediation priority for exposed or business-critical Alfresco environments. Require rapid inventory, vendor-guidance confirmation, access restriction where necessary, patching, and post-remediation verification. Exact version ambiguity should accelerate vendor validation rather than delay action.
Technical view
CVE-2026-26339 is described as argument injection in Alfresco document processing, enabling unauthenticated remote code execution. Its CVSS 3.1 score is 9.8: network-accessible, low complexity, no privileges or user interaction, with high confidentiality, integrity, and availability impact. The supplied CWE-918 classification does not clearly align with the described injection mechanism.
Likely exposure
Potential exposure includes deployments using Alfresco Transformation Service Enterprise or Alfresco Community Transform Core where document-processing functionality is reachable from untrusted networks. The supplied affected-version entries contain only “0” with a default status of unaffected, so they are insufficient for determining precise exposure.
Exploitation context
The source bundle reports no CISA KEV listing and provides no evidence of active exploitation. That does not establish that exploitation is absent. The vulnerability’s remote, unauthenticated, low-complexity characteristics make exposed affected systems particularly concerning.
Researcher notes
The supplied data has notable uncertainty: affected versions are represented only as “0” while default status is unaffected, and CWE-918 is atypical for argument injection. Use Hyland’s advisory and the current CVE record to resolve affected ranges and technical classification. No active exploitation claim is supported.
Mitigation direction
- Inventory Alfresco Transformation Service and Community Transform Core deployments, including versions and network exposure.
- Review Hyland’s security advisory for authoritative affected and fixed release information.
- Apply the Hyland-provided patch or upgrade specified in the advisory after confirming applicability.
- Restrict transformation services from untrusted networks until remediation is verified.
Validation and detection
- Compare installed component editions and versions with Hyland’s affected and fixed release guidance.
- Determine whether document transformation functionality is reachable without authentication from untrusted networks.
- After remediation, confirm installed versions match vendor guidance and transformation workflows still operate correctly.
- Review service and process telemetry for unexpected child processes, unusual arguments, or anomalous transformation failures.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-918: Information exposure and cloud metadata lookup
Information exposure and SSRF weaknesses can make discovery, cloud metadata, and credential material review relevant. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-26339 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
2 official scoresWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N——VulnCheckVulnerability scoring details
Base CVSS 4.0 score
9.3CriticalVector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://connect.hyland.com/t5/alfresco-blog/security-update-cve-2026-26337-cve-2026-26338-cve-2026-26339/ba-p/496551CVE reference, VulnCheck · vendor-advisory, patch
- https://www.hyland.com/en/solutions/products/alfresco-platformCVE reference, VulnCheck · product
- https://www.vulncheck.com/advisories/hyland-alfresco-transformation-service-argument-injection-rceCVE reference, VulnCheck · third-party-advisory
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Server-Side Request Forgery (SSRF)
Server-Side Request Forgery (SSRF) represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.