Activepieces: Reflected Cross-Site Scripting in OAuth Redirect Endpoint

published 2026-08-11 2 mo ago modified 2026-09-09 1 mo ago also EUVD-2026-56552

cvss: 6.1; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 29%
public exploits: 0; none known

Activepieces is an open source AI workflow automation platform. Prior to 0.83.0, the /api/redirect OAuth callback endpoint embeds the user-supplied code query parameter directly into an inline script block without proper escaping. A crafted request to /api/redirect with a malicious code value can break out of the script context and execute arbitrary JavaScript in the Activepieces origin when a logged-in user opens it. An unauthenticated attacker can access the victim's session tokens or make authenticated API calls on the victim's behalf. This issue is fixed in version 0.83.0.

Patch / fix

links 2

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 2 mo ago (2026-08-12)

Exploit prediction

0.36% chance of exploitation in the next 30 days, higher than 29% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	6.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected products

activepieces activepieces

Classification

Weakness

CWE-79 Improper Neutralization of Input During Web Page Generation
CWE-94 Improper Control of Generation of Code

References

Sources

CVE List CVE-2026-73084
NVD CVE-2026-73084

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.

Summary