VulnerabilityPublished 28 Jan 2026Updated 2 Feb 2026

CVE-2025-61730: Go standard library crypto/tls · Improper Verification of Source of a Communication Channel

Affects Go standard library crypto/tlsSource CVE Database V5

Not known to be exploited · CVSS 5.3 Medium : upgrade to 1.25.6 or 1.24.12 when convenient.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score

5.3Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.3% chance of exploitation in 30 days – higher than 25% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 1.25.6, 1.24.12

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 28 Jan 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Go standard library crypto/tls to 1.25.6 or 1.24.12.

Affected software

Product	Affected	Fixed in
Go standard librarycrypto/tls	Affected >=1.25.0 <1.25.6	Fixed in 1.25.6
Go standard librarycrypto/tls	Affected <1.24.12	Fixed in 1.24.12
Gocrypto/tls`pkg:golang/crypto/tls`Other threats	Affected <1.24.12 >=1.25.0 <1.25.6	Fixed in 1.24.12 1.25.6
Gogithub.com/golang/go/src/crypto/tls`pkg:golang/github.com/golang/go/src/crypto/tls`Other threats	Affected =0 =1.25.0	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

European organizations should monitor Go project updates and apply patches promptly once released for versions up to 1.25.0. In the interim, consider mitigating exposure by limiting TLS 1.3 handshake message fragmentation across encryption boundaries, if configurable, or by enforcing strict network controls to prevent message injection by local attackers. Employ network segmentation and robust intrusion detection systems to detect anomalous TLS handshake behaviors. Additionally, organizations should audit their use of the Go crypto/tls package in critical applications and consider temporary workarounds such as disabling TLS 1.3 if feasible and acceptable, or using alternative TLS libraries not affected by this vulnerability. Regularly review network security posture to reduce the risk of local attackers gaining the capability to inject messages. Finally, ensure comprehensive logging and monitoring of TLS handshake failures or anomalies to detect potential exploitation attempts.

Description

During the TLS 1.3 handshake if multiple messages are sent in records that span encryption level boundaries (for instance the Client Hello and Encrypted Extensions messages), the subsequent messages may be processed before the encryption level changes. This can cause some minor information disclosure if a network-local attacker can inject messages during the handshake.

Impact

For European organizations, the primary impact is minor information disclosure during TLS 1.3 handshakes in applications using the Go standard library's crypto/tls package. This could potentially expose sensitive handshake data to network-local attackers capable of injecting messages, which may aid in further reconnaissance or targeted attacks. While the confidentiality impact is limited and does not compromise session keys or encrypted application data, it could weaken the overall security posture. Organizations relying on Go for critical services, especially those handling sensitive or regulated data, may face increased risk of subtle data leaks. The vulnerability does not affect data integrity or availability, so service disruption or data tampering risks are minimal. However, the presence of this flaw could undermine trust in TLS connections and complicate compliance with data protection regulations such as GDPR if sensitive information is leaked. The risk is higher in environments with untrusted or compromised local networks, such as public Wi-Fi or shared infrastructure.

CWE-940Improper Verification of Source of a Communication Channel (opens in a new tab)
Base weaknessOWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
The product establishes a communication channel to handle an incoming request that has been initiated by an actor, but it does not properly verify that the request is coming from the expected origin.
Architecture and Design
Use a mechanism that can validate the identity of the source, such as a certificate, and validate the integrity of data to ensure that it cannot be modified in transit using an Adversary-in-the-Middle (AITM) attack.
OWASP Cheat Sheets
OWASP Authentication (opens in a new tab)
OWASP ASVS 4.0.3
V1.14.1 (opens in a new tab)
V14.5.2 (opens in a new tab)
V14.5.3 (opens in a new tab)
Attack patterns
WebView Injection (opens in a new tab)
Connection Reset (opens in a new tab)
TCP RST Injection (opens in a new tab)
Traffic Injection (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 5 Feb 2026, 08:28 UTC

WeaknessesCWE-940

Technical details

References

Community reviews

Related threats