VulnerabilityPublished 11 Mar 2026

CVE-2026-32128: labring FastGPT · Incomplete List of Disallowed Inputs

Affects labring FastGPTSource CVE Database V5

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Not known to be exploited · CVSS 6.3 Medium.

Data as of 29 Oct 2026, 19:04 UTC

CVSS 3.1 base score

6.3Medium

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 24% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

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

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: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
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: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 11 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: evidence found.
Public exploit code: GitHub proofs of concept
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), GitHub proofs of concept, the Metasploit, Exploit-DB and nuclei-templates index as of 29 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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
labringFastGPT	Affected <=4.14.7	Fixed in–
GitHublabring/FastGPT`pkg:github/labring/FastGPT`Other threats	Affected <=4.14.7	Fixed in–

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

AI-suggested

To mitigate this vulnerability, organizations should upgrade FastGPT to a version later than 4.14.7 once a patch is released that properly restricts file descriptor remapping or enhances seccomp filters to detect and block such bypass attempts. Until a patch is available, consider implementing additional sandboxing layers or container security policies that restrict the use of fcntl or remapping of file descriptors within the sandbox environment. Monitoring and alerting on unusual file descriptor operations or unexpected file writes inside sandbox containers can help detect exploitation attempts. Restricting privileges of processes running inside the sandbox to the minimum necessary and isolating sandbox containers from sensitive host resources reduces potential impact. Additionally, review and harden seccomp profiles to explicitly deny remapping operations or writes to file descriptors other than stdout. Employ runtime integrity checks on sandbox files to detect unauthorized modifications. Finally, maintain strict access controls and audit logs for sandbox usage to facilitate incident response.

Description

CVE-2026-32128 is a medium severity vulnerability affecting FastGPT versions 4.14.7 and earlier. It arises from incomplete input filtering in FastGPT's Python Sandbox, allowing attackers to bypass file write restrictions by remapping stdout to an arbitrary writable file descriptor using fcntl. This bypass enables arbitrary file creation or overwriting inside the sandbox container despite intended protections. Exploitation requires low privileges but no user interaction and can impact confidentiality, integrity, and availability within the sandbox environment. No known exploits are currently reported in the wild. Organizations using FastGPT AI Agent building platform should prioritize patching or mitigating this vulnerability to prevent potential sandbox escape or unauthorized file manipulation. The vulnerability is relevant globally but especially critical in countries with significant AI development and deployment using FastGPT. The CVSS score is 6.

Impact

The vulnerability allows attackers to bypass sandbox file write restrictions, enabling arbitrary file creation or overwriting within the sandbox container. This can lead to unauthorized modification of files, injection of malicious code, or disruption of sandbox operations. For organizations, this could result in compromised AI agent behavior, data leakage, or persistence of malicious payloads within supposedly isolated environments. Since the sandbox is designed to restrict potentially dangerous operations, this bypass undermines trust in the containment mechanism, increasing the risk of broader system compromise if the sandbox is used in multi-tenant or sensitive environments. The impact spans confidentiality (unauthorized data writes), integrity (file tampering), and availability (potential denial of service through file corruption). Although exploitation requires some privileges, the low complexity and lack of user interaction make it a practical threat. Organizations relying on FastGPT for AI agent development or deployment may face operational risks, intellectual property exposure, or compliance issues if this vulnerability is exploited.

CWE-184Incomplete List of Disallowed Inputs (opens in a new tab)
Base weaknessOWASP Top 10 A03:2021: Injection (opens in a new tab)
The product implements a protection mechanism that relies on a list of inputs (or properties of inputs) that are not allowed by policy or otherwise require other action to neutralize before additional processing takes place, but the list is incomplete.
Implementation · Input Validation
Do not rely exclusively on detecting disallowed inputs. There are too many variants to encode a character, especially when different environments are used, so there is a high likelihood of missing some variants. Only use detection of disallowed inputs as a mechanism for detecting suspicious activity.
Attack patterns
Double Encoding (opens in a new tab)
Command Delimiters (opens in a new tab)
Flash Injection (opens in a new tab)
Using Leading 'Ghost' Character Sequences to Bypass Input Filters (opens in a new tab)
Exploiting Multiple Input Interpretation Layers (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

github.com/labring/FastGPT/security/advisories/GHSA-6hw6-mxrm-v6wj (opens in a new tab)

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 19 Mar 2026, 02:27 UTC

Public exploits and detectionGitHub proofs of concept

WeaknessesCWE-184

Technical details

References

Community reviews

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