VulnerabilityPublished 26 Oct 2026

CVE-2026-110314: mtrudel bandit · Client-Side Enforcement of Server-Side Security

Affects mtrudel banditSource CVE Database V5

Not known to be exploited · CVSS 6.3 Medium : upgrade to 1.14.0 when convenient.

Data as of 26 Oct 2026, 16:53 UTC

CVSS 4.0 base score

6.3Medium

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

Patch: Available – fixed in 1.14.0, 220b9dfd27f9a21305be2afc75cbe585ddc24e7a

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: Present
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: Low
Vulnerable system integrity: Low
Vulnerable system availability: None
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

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

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, 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: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: Present: The successful attack depends on the presence of specific deployment and execution conditions of the vulnerable system that enable the attack. These include: a race condition must be won to successfully exploit the vulnerability (the successfulness of the attack is conditioned on execution conditions that are not under full control of the attacker, or the attack may need to be launched multiple times against a single target before being successful); the attacker must inject themselves into the logical network path between the target and the resource requested by the victim (e.g. vulnerabilities requiring an on-path attacker).
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system 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 Vulnerable System.
Vulnerable system 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 to the Vulnerable System.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 26 Oct 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 bandit to 1.14.0; bandit to 220b9dfd27f9a21305be2afc75cbe585ddc24e7a.

Affected software

Product	Affected	Fixed in
mtrudelbandit	Affected >=0.5.1 <1.14.0	Fixed in 1.14.0
banditmtrudel/bandit	Affected ≥ bb407f2277dcb65a58dd8cc07913a0b58a80e266, < 220b9dfd27f9a21305be2afc75cbe585ddc24e7a	Fixed in 220b9dfd27f9a21305be2afc75cbe585ddc24e7a
Hexbandit`pkg:hex/bandit`Other threats	Affected >=0.5.1 <1.14.0	Fixed in 1.14.0

CPE configurations (1)

cpe:2.3:a:mtrudel:bandit:*:*:*:*:*:*:*:*

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

AI-suggested

Upgrade bandit to version 1.14.0 or later, where this vulnerability is fixed. No other mitigation is indicated by the vendor advisory.

Description

CVE-2026-110314 is a vulnerability in the mtrudel bandit WebSocket connection handling where client-side enforcement incorrectly allows continued execution of WebSocket handler code after the server has sent a Close frame. This flaw enables a remote client to send data frames that are processed despite the server intending to close the connection, potentially allowing unauthorized actions such as admin-only operations. The issue affects bandit versions from 0.5.1 up to but not including 1.14.0 and is fixed in version 1.14.0.

Impact

An attacker can exploit this vulnerability to continue interacting with the WebSocket connection after the server has attempted to close it, potentially bypassing server-side security checks. This could allow unauthorized execution of admin-only actions or other privileged operations. The CVSS 4.0 score of 6.3 reflects a medium severity with network attack vector, low attack complexity, and partial impact on confidentiality and integrity.

Summary

The vulnerability arises because after a WebSocket callback returns a stop tuple, Bandit.WebSocket.Connection sends a Close frame and shuts down the write side but keeps the connection process running in a closing state. However, the handlers for incoming frames and messages do not check this closing state, allowing subsequent frames and messages to be processed with the state from the stop tuple. This can lead to a client that was refused during initialization (e.g., due to a failed token check) still executing privileged actions. The flaw is present in bandit versions >=0.5.1 and <1.14.0 and is resolved in version 1.14.0.

CWE-602Client-Side Enforcement of Server-Side Security (opens in a new tab)
Class weaknessLikelihood of exploit: MediumOWASP Top 10 A06:2025: Insecure Design (opens in a new tab)
The product is composed of a server that relies on the client to implement a mechanism that is intended to protect the server.
Architecture and Design
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely.
Architecture and Design
If some degree of trust is required between the two entities, then use integrity checking and strong authentication to ensure that the inputs are coming from a trusted source.
OWASP Cheat Sheets
Docker Security (opens in a new tab)
Abuse Case (opens in a new tab)
Deserialization (opens in a new tab)
Access Control (opens in a new tab)
Authorization Testing Automation (opens in a new tab)
OWASP ASVS 4.0.3
V1.4.1 (opens in a new tab)
V1.5.3 (opens in a new tab)
V4.1.1 (opens in a new tab)
Attack patterns
Manipulating Hidden Fields (opens in a new tab)
Create Malicious Client (opens in a new tab)
Removing Important Client Functionality (opens in a new tab)
Removing/short-circuiting 'Purse' logic: removing/mutating 'cash' decrements (opens in a new tab)
Accessing/Intercepting/Modifying HTTP Cookies (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

CPE configurations (1)

Description

AI analysisMachine-generated, updated 26 Oct 2026, 14:17 UTC

WeaknessesCWE-602

Technical details

References

Community reviews

Related threats