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GoApplication · Golang

CVE-2025-68121

CRITICAL · 10.0 CVSS v3.1 Published 2026-02-05
Fix available
A fix is available. Upgrade to 1.24.13 / 1.25.7 or later.
See remediation →
100/100
Remediation priority · Urgent
Public exploit Remotely reachable No privileges Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Go crypto/tls session resumption vulnerability where mutating Config.ClientCAs or Config.RootCAs between initial and resumed handshake (via Config.Clone() or GetConfigForClient) allows sessions to resume with certificates that would have failed the initial handshake, enabling connections to untrusted entities.

MitigationAudit TLS code for Config.Clone() or GetConfigForClient usage that modifies ClientCAs/RootCAs; ensure CA configurations remain immutable between initial handshake and session resumption, or implement explicit validation to reject resumed sessions when CA trust has changed.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
GoApplication
Affected:< 1.24.13>= 1.25.0, < 1.25.7= 1.26.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check the installed Go version
    Run 'go version' to identify the Go runtime version
    Affected if The version is < 1.24.13, or >= 1.25.0 and < 1.25.7, or exactly 1.26.0
  2. Identify TLS servers using session resumption
    Search codebase for usage of tls.Config with SessionTicketsEnabled or GetConfigForClient, and review any TLS server implementations that call Config.Clone
    Affected if TLS servers with session resumption enabled exist in the codebase
  3. Check for mutation of ClientCAs or RootCAs after handshake
    Search for code patterns where Config.ClientCAs or Config.RootCAs are assigned or modified after tls.Server or tls.Client is created, or after Config.Clone() is called
    Affected if ClientCAs or RootCAs are modified between initial handshake and any potential session resumption
  4. Review GetConfigForClient for CA consistency
    Audit any GetConfigForClient callback implementations to verify they return the same ClientCAs/RootCAs for the same client across calls
    Affected if GetConfigForClient returns different CA configurations for the same client identity

You are affected if running a vulnerable Go version AND using TLS session resumption with mutable or inconsistent CA configurations in ClientCAs or RootCAs

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 1.24.13 / 1.25.7 or later
Fixed in 1.24.131.25.7
Vendor patch go.dev →
Interim mitigation

Audit TLS code for Config.Clone() or GetConfigForClient usage that modifies ClientCAs/RootCAs; ensure CA configurations remain immutable between initial handshake and session resumption, or implement explicit validation to reject resumed sessions when CA trust has changed.

Recommended fix High confidence

Go 1.24.13, 1.25.7, 1.26.1, or later (prefer latest stable release)

  1. 1. Identify the current Go version by running: go version
  2. 2. If running Go < 1.24.13, upgrade to Go 1.24.13 or later (e.g., go install golang.org/dl/go1.24.13@latest && go1.24.13 download)
  3. 3. If running Go >= 1.25.0 and < 1.25.7, upgrade to Go 1.25.7 or later
  4. 4. If running Go 1.26.0, upgrade to Go 1.26.1 or later
  5. 5. Verify the upgrade was successful by running: go version
  6. 6. Rebuild and redeploy all applications that use crypto/tls to ensure they use the fixed Go runtime
  7. 7. Test TLS functionality, especially session resumption, to confirm the fix works correctly

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Go Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-68121 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data