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Fencer Vulns
high 8.9

CVE-2026-27169 json

OpenSift: Persistent XSS Chat Tool Rendering

published 2026-02-20 8 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-7746

cvss
8.9
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 33%
public exploits
0
none known

Summary

OpenSift is an AI study tool that sifts through large datasets using semantic search and generative AI. Versions 1.1.2-alpha and below render untrusted user/model content in chat tool UI surfaces using unsafe HTML interpolation patterns, leading to XSS. Stored content can execute JavaScript when later viewed in authenticated sessions. An attacker who can influence stored study/quiz/flashcard content could trigger script execution in a victim’s browser, potentially performing actions as that user in the local app session. This issue has been fixed in version 1.1.3-alpha.

Patch / fix

  • opensift opensift 1.1.3

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
8 mo ago

Exploit prediction

0.39% chance of exploitation in the next 30 days, higher than 33% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.9 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:L

Affected products

  • OpenSift OpenSift

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation
  • CWE-116 Improper Encoding or Escaping of Output

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.