CVE-2026-57857Network attack vector

Reflected XSS via unsanitized error_message parameter

Published Jul 18, 2026 · Updated Jul 18, 2026

Reflected cross-site scripting in Flow's Pasarela Flow for WooCommerce 3.0.8 allows remote attackers to run script via a crafted checkout URL. The cancellation handler in flowpayment-fl.php passes the error_message query value directly to wc_add_notice without sanitizing or escaping it before notice rendering. Exploitation requires a victim with an active WooCommerce checkout session to follow the crafted link, after which the script runs in the site's browser origin.

CVSS severity5.1
Medium
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected cross-site scripting in Flow's Pasarela Flow for WooCommerce 3.0.8 allows remote attackers to run script via a crafted checkout URL. The cancellation handler in flowpayment-fl.php passes the error_message query value directly to wc_add_notice without sanitizing or escaping it before notice rendering. Exploitation requires a victim with an active WooCommerce checkout session to follow the crafted link, after which the script runs in the site's browser origin.

The record

CVE
CVE-2026-57857
Published
Jul 18, 2026
Updated
Jul 18, 2026
Vendor
Flow
Product
Pasarela Flow for WooCommerce
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 18, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=3.0.8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Flow · Pasarela Flow for WooCommerceversion=0 <=3.0.8

Published CVSS scores

5.1VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
4.3VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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