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Open-source package vulnerability · Go

CVE-2026-39834: golang.org/x/crypto vulnerable to infinite loop on large channel writes

criticalCVSS 3.1 9.1GHSA-rm3j-f69w-wqmq

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.

Published Jun 25, 2026 · Updated Jul 7, 2026

Affected packages

golang.org/x/crypto

Ecosystem
Go
Affected
< 0.52.0
Fixed in
0.52.0
Check
go list -m golang.org/x/crypto

Advisory details

From the GitHub Advisory Database (CC BY 4.0).

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.

References

How this page is made: the data panel comes from the GitHub Advisory Database, CISA’s KEV catalog, the NVD and FIRST EPSS, and updates twice a day. No analysis has been written for this entry yet. Methodology

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