VulnerabilityPublished 13 Nov 2025Updated 16 Dec 2025

CVE-2025-47913: golang.org/x/crypto/ssh/agent · Improper Handling of Exceptional Conditions

Affects golang.org/x/crypto/ssh/agentSource CVE Database V5

Not known to be exploited · CVSS 7.5 High.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score

7.5High

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

EPSS: 0.6% chance of exploitation in 30 days – higher than 51% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

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

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: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 13 Nov 2025
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

Affected software

Product	Affected	Fixed in
Gogolang.org/x/crypto/ssh/agent`pkg:golang/golang.org/x/crypto/ssh/agent`Other threats	Affected *	Fixed in–

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AI-suggested

Organizations should monitor for official patches or updates from the golang.org/x/crypto project and apply them promptly once available. In the interim, developers should implement additional error handling around SSH agent responses to catch unexpected message types and prevent client panics. Employing SSH client wrappers or middleware that validate and sanitize agent responses can reduce risk. Network-level controls to restrict or monitor SSH agent communication may help detect anomalous messages indicative of exploitation attempts. Additionally, organizations should audit their Go-based SSH client usage to identify affected versions and consider temporary workarounds such as disabling SSH agent forwarding where feasible. Incorporating robust logging and alerting on SSH client crashes will aid in early detection of exploitation attempts. Finally, educating development and operations teams about this vulnerability ensures preparedness for patch deployment and incident response.

Description

CVE-2025-47913 is a high-severity vulnerability in the golang.org/x/crypto SSH agent package where SSH clients panic and terminate unexpectedly upon receiving an SSH_AGENT_SUCCESS message when a typed response is expected. This improper handling of exceptional conditions (CWE-703) leads to denial of service by crashing the client process without requiring authentication or user interaction. The vulnerability affects all versions of the golang.org/x/crypto/ssh/agent package and has a CVSS score of 7.5, indicating significant impact on availability. No known exploits are currently reported in the wild. European organizations using Go-based SSH clients that rely on this package may face service disruptions, particularly in critical infrastructure and development environments. Mitigation involves updating to patched versions once available and implementing robust error handling around SSH agent responses. Countries with strong software development sectors and critical infrastructure relying on Go are most at risk, including Germany, France, the UK, and the Netherlands.

Impact

For European organizations, the primary impact is denial of service through unexpected termination of SSH client processes, which can disrupt secure shell sessions, automated deployment pipelines, and remote management tasks. This can lead to operational downtime, loss of productivity, and potential delays in critical infrastructure management or software development workflows. Since the vulnerability does not affect confidentiality or integrity, data breaches are unlikely; however, availability disruptions can have cascading effects, especially in sectors like finance, telecommunications, energy, and government services that rely heavily on SSH for secure remote access. The lack of required privileges or user interaction means attackers can exploit this vulnerability remotely and silently, increasing the risk of widespread disruption. Organizations using Go-based tooling or custom SSH clients embedding this package are particularly vulnerable. The absence of known exploits provides a window for proactive mitigation but also means attackers may develop exploits in the future.

Summary

CVE-2025-47913 is a vulnerability classified under CWE-703 (Improper Handling of Exceptional Conditions) found in the golang.org/x/crypto/ssh/agent package, a widely used Go library for SSH agent communication. The flaw occurs when an SSH client receives an SSH_AGENT_SUCCESS message while expecting a typed response; instead of handling this gracefully, the client panics and terminates prematurely. This behavior results from inadequate validation and error handling in the SSH agent client code, causing a denial-of-service (DoS) condition by crashing the client process. The vulnerability affects all versions of the package as indicated, with no patches currently available. The CVSS 3.1 score of 7.5 reflects a high severity due to the network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), unchanged scope (S:U), no impact on confidentiality or integrity (C:N/I:N), but a high impact on availability (A:H). Although no known exploits are reported in the wild, the vulnerability could be exploited remotely by an attacker capable of injecting or manipulating SSH agent responses, causing client crashes and disrupting automated or manual SSH operations. This is particularly critical in environments relying on Go-based SSH clients for secure communications and automation.

CWE-703Improper Check or Handling of Exceptional Conditions (opens in a new tab)
Pillar weaknessOWASP Top 10 A10:2025: Mishandling of Exceptional Conditions (opens in a new tab)
The product does not properly anticipate or handle exceptional conditions that rarely occur during normal operation of the product.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
OWASP Cheat Sheets
Logging (opens in a new tab)
Error Handling (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 23 Dec 2025, 17:23 UTC

WeaknessesCWE-703

Technical details

References

Community reviews

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