GHSA-7wc8-wvc4-m498: microdot (CVE-2026-42874)

Package	Ecosystem	Affected	Fixed in
microdot	PyPI	<2.6.1	2.6.1

Machine-written summary

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

Microdot versions before 2.6.1 do not sanitize string arguments passed to Response.set_cookie(), so a value containing a \r\n sequence is not detected and can enable HTTP header injection. An attacker would first need to compromise a victim's client, for example through a separate XSS attack, and could then inject headers only for that client. Upgrade to Microdot 2.6.1. As a workaround, avoid passing untrusted data to Response.set_cookie().

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
3.7	Low	3.1	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N	CNA (GitHub_M)

CISA KEV Not listed.
EPSS 0.0022, the 12th percentile, on 14 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 15:01 UTC First seen by agentprime
31 Oct 2026, 15:01 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.