GHSA-9fww-8cpr-q66r: isso (CVE-2026-27469)

Package	Ecosystem	Affected	Fixed in
isso	PyPI	<0.13.2	0.13.2

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Isso versions before 0.13.2 are vulnerable to stored cross-site scripting through the comment website field, which is not properly escaped and can break out of an HTML attribute. An anonymous attacker can post a comment with a crafted website URL, and the script then runs in the browser of any visitor to a page showing that comment, with no interaction beyond moving the mouse. Upgrade to isso 0.13.2 or later. Enabling comment moderation reduces exposure but does not fully prevent the issue.

Written 6 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
6.1	Medium	3.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N	CNA (GitHub_M)

CISA KEV Not listed.
EPSS 0.0026, the 17th percentile, on 8 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 15:02 UTC First seen by agentprime
31 Oct 2026, 15:02 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.