How severe is CVE-2025-68121?

CVE-2025-68121 has a CVSS 3.x base score of 10.0, 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 high, and availability high.

Is CVE-2025-68121 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (51st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-68121?

CVE-2025-68121 primarily affects Golang Go. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2025-68121?

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-2025-68121 have an EU (EUVD) identifier?

Yes. CVE-2025-68121 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-206854.

When was CVE-2025-68121 published?

CVE-2025-68121 was published on 2026-02-05 and last updated on 2026-06-17.

CVE-2025-68121

CVE-2025-68121 is a critical-severity vulnerability in Golang Go with a CVSS 3.x base score of 10.0. 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-295.

Key facts

Severity: Critical (CVSS 3.x base score 10.0)
EPSS exploit prediction: 1% (51st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-206854
Weakness: CWE-295
Affected product: Golang Go
Published: 2026-02-05
Last modified: 2026-06-17

Description

During session resumption in crypto/tls, if the underlying Config has its ClientCAs or RootCAs fields mutated between the initial handshake and the resumed handshake, the resumed handshake may succeed when it should have failed. This may happen when a user calls Config.Clone and mutates the returned Config, or uses Config.GetConfigForClient. This can cause a client to resume a session with a server that it would not have resumed with during the initial handshake, or cause a server to resume a session with a client that it would not have resumed with during the initial handshake.

Frequently asked questions

What is CVE-2025-68121?: During session resumption in crypto/tls, if the underlying Config has its ClientCAs or RootCAs fields mutated between the initial handshake and the resumed handshake, the resumed handshake may succeed when it should have failed. This may happen when a user calls Config.Clone and mutates the returned Config, or uses Config.GetConfigForClient. This can cause a client to resume a session with a server that it would not have resumed with during the initial handshake, or cause a server to resume a session with a client that it would not have resumed with during the initial handshake.
How severe is CVE-2025-68121?: CVE-2025-68121 has a CVSS 3.x base score of 10.0, 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 high, and availability high.
Is CVE-2025-68121 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (51st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-68121?: CVE-2025-68121 primarily affects Golang Go. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2025-68121?: 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-2025-68121 have an EU (EUVD) identifier?: Yes. CVE-2025-68121 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-206854.
When was CVE-2025-68121 published?: CVE-2025-68121 was published on 2026-02-05 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:golang:go:*:*:*:*:*:*:*:*
cpe:2.3:a:golang:go:1.26.0:rc1:*:*:*:*:*:*
cpe:2.3:a:golang:go:1.26.0:rc2:*:*:*:*:*:*

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