CVE-2025-68121
Unexpected session resumption in crypto/tls
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.
INFO
Published Date :
Feb. 5, 2026, 6:16 p.m.
Last Modified :
Feb. 20, 2026, 5:25 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | ||||
| CVSS 3.1 | CRITICAL | [email protected] | ||||
| CVSS 3.1 | HIGH | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
Solution
- Do not mutate TLS Config CAs after initial handshake.
- Avoid cloning and mutating Config after handshake.
- Use GetConfigForClient cautiously with Config CAs.
Public PoC/Exploit Available at Github
CVE-2025-68121 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2025-68121.
| URL | Resource |
|---|---|
| https://go.dev/cl/737700 | Patch |
| https://go.dev/issue/77217 | Exploit Issue Tracking |
| https://groups.google.com/g/golang-announce/c/K09ubi9FQFk | Mailing List Third Party Advisory |
| https://pkg.go.dev/vuln/GO-2026-4337 | Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-68121 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2025-68121
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
All Public RunWhen Helm Charts - Managed by terraform
Shell Dockerfile Go Template
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2025-68121 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2025-68121 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Feb. 20, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N Removed CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N -
Initial Analysis by [email protected]
Feb. 10, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H Added CPE Configuration OR *cpe:2.3:a:golang:go:*:*:*:*:*:*:*:* versions up to (excluding) 1.24.13 *cpe:2.3:a:golang:go:*:*:*:*:*:*:*:* versions from (including) 1.25.0 up to (excluding) 1.25.7 *cpe:2.3:a:golang:go:1.26.0:rc1:*:*:*:*:*:* *cpe:2.3:a:golang:go:1.26.0:rc2:*:*:*:*:*:* Added Reference Type Go Project: https://go.dev/cl/737700 Types: Patch Added Reference Type Go Project: https://go.dev/issue/77217 Types: Exploit, Issue Tracking Added Reference Type Go Project: https://groups.google.com/g/golang-announce/c/K09ubi9FQFk Types: Mailing List, Third Party Advisory Added Reference Type Go Project: https://pkg.go.dev/vuln/GO-2026-4337 Types: Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Feb. 06, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N Added CWE CWE-295 -
New CVE Received by [email protected]
Feb. 05, 2026
Action Type Old Value New Value Added 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. Added Reference https://go.dev/cl/737700 Added Reference https://go.dev/issue/77217 Added Reference https://groups.google.com/g/golang-announce/c/K09ubi9FQFk Added Reference https://pkg.go.dev/vuln/GO-2026-4337