CVE-2026-39834
Invoking infinite loop on large channel writes in golang.org/x/crypto/ssh
9.1
CRITICAL
CVSS 3.1
EPSS 0.05%
Description
When writing data larger than 4GB in a single Write call on an SSH channel, an integer overflow in the internal payload size calculation caused the write loop to spin indefinitely, sending empty packets without making progress. The size comparison now uses int64 to prevent truncation.
How to fix CVE-2026-39834
To remediate CVE-2026-39834, upgrade the affected package to a fixed version below.
- —no fix listed
- —upgrade to 0.52.0 or later
Is CVE-2026-39834 being exploited?
Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0
- from 0, < 0.52.0
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | CRITICAL9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H |