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Fencer Vulns
medium 5.3

CVE-2026-53536 json

Activepieces: Cross-tenant file download via missing JWT audience check on step-files signed URL

published 2026-07-16 3 mo ago modified 2026-07-18 3 mo ago also EUVD-2026-45027

cvss
5.3
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 14%
public exploits
0
none known

Summary

Activepieces is an open source AI workflow automation platform. Prior to 0.83.0, the /v1/step-files/signed download endpoint verified the supplied JWT against the shared signing secret but did not check the token's audience, and combined with a missing null-check on the decoded fileId, this allowed any caller holding any valid Activepieces JWT (including a freshly created user's own access token) to receive a step-file belonging to another tenant. The file returned was whatever PostgreSQL happened to scan first for type = FLOW_STEP_FILE, varying over time as the database changed, so an authenticated user could obtain step-file attachments belonging to other tenants on the same instance; the attacker could not target a specific victim or file, and the access was read-only with no integrity or availability impact. This issue is fixed in version 0.83.0.

Patch / fix

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 14% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 5.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
CNA 4.0 5.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • activepieces activepieces

Classification

Weakness
  • CWE-345 Insufficient Verification of Data Authenticity
  • CWE-639 Authorization Bypass Through User-Controlled Key

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.