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Fencer Vulns
medium 4.3

CVE-2026-55566 json

Yamcs: DOM XSS in Extension Routing

published 2026-08-28 2 mo ago modified 2026-09-08 2 mo ago also EUVD-2026-67845 , GHSA-9272-wg2r-7xmx

cvss
4.3
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 32%
public exploits
0
none known

Summary

Yamcs is a mission control framework. Prior to 5.12.8 and 5.13.2, Yamcs processes attacker-controlled data from the /ext URL route in yamcs-web/src/main/webapp/projects/webapp/src/app/core/routes/extension.matcher.ts, extension.component.ts, and app.component.ts without checking registered plugin IDs before DOM rendering through innerHTML. A crafted URL can execute JavaScript when opened by a user. The script can read data available to the Yamcs web application and perform actions in the user context. This issue is fixed in versions 5.12.8 and 5.13.2.

Patch / fix

  • maven org.yamcs:yamcs-core 5.12.8, 5.13.2
  • org.yamcs yamcs-core 5.12.8, 5.13.2
  • spaceapplications yamcs 5.12.8, 5.13.2

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.38% chance of exploitation in the next 30 days, higher than 32% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/yamcs/yamcs/security/advisories/GHSA-9272-wg2r-7xmx referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
GitHub 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

Affected packages

ecosystem package affected fixed in
maven org.yamcs:yamcs-core
>=5.13.0, <5.13.2
<5.12.8
5.13.2
5.12.8

Affected products

  • yamcs yamcs

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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.