Unexpected session resumption in crypto/tls

Answer in brief

CVE-2025-68121 records a Unknown severity vulnerability in Unexpected session resumption in crypto/tls. The current sources do not mark it as known exploited. The current feed maps stdlib (go). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Feb 5, 2026Updated Sep 4, 2026Source checked Sep 6, 2026First seen by HOL Aug 14, 2026Material review Sep 4, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps stdlib (go). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
stdlibgo	>=0 <1.24.13 >=1.25.0-0 <1.25.7 >=1.26.0-rc.1 <1.26.0-rc.3	1.24.13, 1.25.7, 1.26.0-rc.3

Recommended response

Check inventory. Check lockfiles and deployed manifests for stdlib.
Review the reported fix. Update stdlib to 1.24.13 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Feb 5, 2026
Evidence: source:osv:source_dates:source-dates:record
Source modified
Sep 4, 2026
Evidence: source:osv:source_dates:source-dates:record
First seen by HOL
Aug 14, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.