How severe is CVE-2026-39830?

CVE-2026-39830 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability high.

Is CVE-2026-39830 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (47th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-39830?

CVE-2026-39830 affects Golang Crypto. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-39830?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-39830 have an EU (EUVD) identifier?

Yes. CVE-2026-39830 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-31397.

When was CVE-2026-39830 published?

CVE-2026-39830 was published on 2026-05-22 and last updated on 2026-08-21.

CVE-2026-39830

CVE-2026-39830 is a critical-severity vulnerability in Golang Crypto with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-119.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
EPSS exploit prediction: 1% (47th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-31397
Weakness: CWE-119
Affected product: Golang Crypto
Published: 2026-05-22
Last modified: 2026-08-21

Description

A malicious SSH peer could send unsolicited global request responses to fill an internal buffer, blocking the connection's read loop. The blocked goroutine could not be released by calling Close(), resulting in a resource leak per connection. Unsolicited global responses are now discarded.

Frequently asked questions

What is CVE-2026-39830?: A malicious SSH peer could send unsolicited global request responses to fill an internal buffer, blocking the connection's read loop. The blocked goroutine could not be released by calling Close(), resulting in a resource leak per connection. Unsolicited global responses are now discarded.
How severe is CVE-2026-39830?: CVE-2026-39830 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability high.
Is CVE-2026-39830 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (47th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-39830?: CVE-2026-39830 affects Golang Crypto. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-39830?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-39830 have an EU (EUVD) identifier?: Yes. CVE-2026-39830 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-31397.
When was CVE-2026-39830 published?: CVE-2026-39830 was published on 2026-05-22 and last updated on 2026-08-21.

References

Affected products (1)

cpe:2.3:a:golang:crypto:*:*:*:*:*:go:*:*

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