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GHSA-rm3j-f69w-wqmq: golang.org/x/crypto vulnerable to infinite loop on large channel writes

criticalCVSS 9.1CVE-2026-39834
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.

Details

Source
GitHub Security Advisories (INTL · database · site)
Severity
critical — CVSS 9.1
Published
2026-06-25
Last updated
2026-07-07
Exploitation
Not in CISA KEV at last sync

Original advisory: https://github.com/advisories/GHSA-rm3j-f69w-wqmq

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Referenced CVEs

CVECSIRTS overviewExternal
CVE-2026-39834coverage & exploitation statusNVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

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