Evidence used
- No CISA KEV confirmation is currently recorded.
- A structured source references public exploit or proof-of-concept material.
- EPSS is 0.59% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2026
CVE-2026-32731High confidence
ApostropheCMS has Arbitrary File Write (Zip Slip / Path Traversal) in Import-Export Gzip Extraction
apostrophecms · import-export
Official source article: GitHub GHSA-MWXC-M426-3F78 ↗. Check the applicable product and release in the original source.
10.0CriticalCVSS 3.1
Within 72 hours
Fix not verifiedCritical technical impact and a public exploit reference; no CISA KEV confirmation is currently recorded.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityCritical→Operational priority:Critical, unchanged from published severity.unchanged
Compensating controls
- Restrict the affected network interface to trusted sources where business-safe.
- Increase monitoring for the attack path and post-exploitation behaviour described in the report.
Verification
- Confirm that the asset runs apostrophecms import-export and falls inside the recorded affected range.
- Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
- Validate exposure, authentication requirements and compensating controls in the actual environment.
- Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Open-source package ranges1 source-attributed range
These OSV and GitHub advisory ranges apply only to the named package and ecosystem. A listed fixed version is not a universal product patch or proof that an update is installed.
| Ecosystem and package | Affected range | First fixed version | Evidence |
|---|---|---|---|
| npm@apostrophecms/import-export | <= 3.5.2 | 3.5.3 | GitHub advisory ↗upstream repository advisory · 18 Mar 2026 |
Critical technical impact and a public exploit reference; no CISA KEV confirmation is currently recorded.
Fix not verified01
What, why and how
ApostropheCMS is an open-source content management framework. Prior to version 3.5.3 of `@apostrophecms/import-export`, The `extract()` function in `gzip.js` constructs file-write paths using `fs.createWriteStream(path.join(exportPath, header.name))`. `path.join()` does not resolve or sanitise traversal segments such as `../`. It concatenates them as-is, meaning a tar entry named `../../evil.js` resolves to a path outside the intended extraction directory. No canonical-path check is performed before the write stream is opened. This is a textbook Zip Slip vulnerability. Any user who has been granted the Global Content Modify permission — a role routinely assigned to content editors and site managers — can upload a crafted `.tar.gz` file through the standard CMS import UI and write attacker-controlled content to any path the Node.js process can reach on the host filesystem. Version 3.5.3 of `@apostrophecms/import-export` fixes the issue.
What
ApostropheCMS is an open-source content management framework. Prior to version 3.5.3 of `@apostrophecms/import-export`, The `extract()` function in `gzip.js` constructs file-write paths using `fs.createWriteStream(path.join(exportPath, header.name))`. `path.join()` does not resolve or sanitise traversal segments such as `../`. It concatenates them as-is, meaning a tar entry named `../../evil.js` resolves to a path outside the intended extraction directory. No canonical-path check is performed before the write stream is opened. This is a textbook Zip Slip vulnerability. Any user who has been granted the Global Content Modify permission — a role routinely assigned to content editors and site managers — can upload a crafted `.tar.gz` file through the standard CMS import UI and write attacker-controlled content to any path the Node.js process can reach on the host filesystem. Version 3.5.3 of `@apostrophecms/import-export` fixes the issue.
Why
Attacker-controlled path data is not constrained to the intended directory before the application accesses a file.
How
An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
What
ApostropheCMS is an open-source content management framework. Prior to version 3.5.3 of `@apostrophecms/import-export`, The `extract()` function in `gzip.js` constructs file-write paths using `fs.createWriteStream(path.join(exportPath, header.name))`. `path.join()` does not resolve or sanitise traversal segments such as `../`. It concatenates them as-is, meaning a tar entry named `../../evil.js` resolves to a path outside the intended extraction directory. No canonical-path check is performed before the write stream is opened. This is a textbook Zip Slip vulnerability. Any user who has been granted the Global Content Modify permission — a role routinely assigned to content editors and site managers — can upload a crafted `.tar.gz` file through the standard CMS import UI and write attacker-controlled content to any path the Node.js process can reach on the host filesystem. Version 3.5.3 of `@apostrophecms/import-export` fixes the issue.
Why
Attacker-controlled path data is not constrained to the intended directory before the application accesses a file.
How
An attacker operating through a network path may attempt exploitation with low privileges. 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 No confirmed evidence
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.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 Reference recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.
- Likely attack path
- a network path → Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') → cause the confidentiality, integrity or availability impact described by the vendor
- 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
- Changed: exploitation can affect a different security authority
- Weakness
?
CWE means Common Weakness Enumeration: a standard category for the underlying weakness. - CWE-22 ↗
CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'). The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
- 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:C/C:H/I:H/A:HCommon 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.SChangedScope: The attack can affect a component governed by a different security authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.- 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.
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
- import-export: < 3.5.3
- 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 18 Mar 2026 · Last source change 19 Mar 2026, 16:04 UTC · CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source FIRST · tracked since 2026-08-14
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2026-12978
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
View recent updates ↗What changed after publication
No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.
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.