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Fencer Vulns
medium 6.1

CVE-2019-20437 json

An issue was discovered in WSO2 API Manager 2.6.0, WSO2 IS as Key Manager 5.7.0, and WSO2 Identity Server 5.8.0.

published 2020-01-27 6 y ago modified 2026-06-17 4 mo ago also EUVD-2019-10985

cvss
6.1
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.3%
EPSS 1.3% chance of exploitation in 30 days, percentile 70%
public exploits
0
none known

Summary

An issue was discovered in WSO2 API Manager 2.6.0, WSO2 IS as Key Manager 5.7.0, and WSO2 Identity Server 5.8.0. When a custom claim dialect with an XSS payload is configured in the identity provider basic claim configuration, that payload gets executed, if a user picks up that dialect's URI as the provisioning claim in the advanced claim configuration of the same Identity Provider. The attacker also needs to have privileges to log in to the management console, and to add and update identity provider configurations.

Exploit prediction

1.28% chance of exploitation in the next 30 days, higher than 70% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/cybersecurityworks/Disclosed/issues/20 referenced PoC, tagged "exploit" by a source, unverified
  • cybersecurityworks.com https://cybersecurityworks.com/zerodays/cve-2019-20437-wso2.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.0 6.1 CVSS:3.0/AC:L/AV:N/A:N/C:L/I:L/PR:N/S:C/UI:R
NVD 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CNA 3.0 6.1 CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:P/A:N

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

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.