GHSA-qr67-gv47-xwwh: asyncssh (CVE-2026-54590)

Package	Ecosystem	Affected	Fixed in
asyncssh	PyPI	<2.23.1	2.23.1

Machine-written summary

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

The asyncssh package, versions before 2.23.1, has an incomplete fix for CVE-2026-45309. A username beginning with a tilde, or containing an environment-variable reference, can bypass the guard that blocks path separators when AuthorizedKeysFile uses %u as its leading component. An unauthenticated remote client can then cause the server to read an authorized-keys file from another account's home directory, which may allow login as that user if a matching key is present. Upgrade to asyncssh 2.23.1, which is the listed fixed version.

Written 1 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
5.9	Medium	3.1	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N	CNA (GitHub_M)

CISA KEV Not listed.
EPSS 0.0034, the 27th percentile, on 12 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 14:10 UTC First seen by agentprime
31 Oct 2026, 14:10 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.