VulnerabilityPublished 1 Mar 2026Updated 2 Mar 2026

CVE-2026-3384: ChaiScript · Uncontrolled Recursion

Affects ChaiScriptSource CVE Database V5

Compare

Public exploit available · CVSS 4.8 Medium.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 4.0 base score

4.8Medium

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

EPSS: 0.1% chance of exploitation in 30 days – higher than 8% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Base metrics

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

Threat metrics

Exploit Maturity: POC

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

Attack Vector: Local: The vulnerable system is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or through terminal emulation (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., using social engineering techniques to trick a legitimate user into opening a malicious document).
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: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: Low: The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system 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 Vulnerable System 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 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.
Exploit Maturity: POC: Based on threat intelligence sources each of the following must apply: · Proof-of-concept is publicly available · No knowledge of reported attempts to exploit this vulnerability · No knowledge of publicly available solutions used to simplify attempts to exploit the vulnerability

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 1 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: evidence found.
CVSS exploit maturity: proof of concept public
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), CVSS vector, 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
ChaiScript	Affected =6.0 =6.1.0	Fixed in–
GitHubchaiscript/ChaiScript`pkg:github/chaiscript/ChaiScript`Other threats	Affected =6.0 =6.1.0	Fixed in–

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

AI-suggested

To mitigate CVE-2026-3384, organizations should first assess whether they use affected versions of ChaiScript (6.0 or 6.1.0) in their environments. 2) Implement strict input validation and sanitization on scripts or data processed by ChaiScript to prevent malicious recursive constructs. 3) Introduce resource limits such as maximum recursion depth or execution timeouts within the scripting environment or host application to prevent runaway recursion. 4) If feasible, disable or sandbox scripting capabilities where untrusted code execution is possible. 5) Monitor logs and system behavior for signs of excessive recursion or resource exhaustion. 6) Engage with the ChaiScript community or maintainers for updates or unofficial patches. 7) Consider upgrading to future versions once a fix is released. These targeted mitigations go beyond generic advice by focusing on controlling recursion and limiting local attack surfaces.

Description

A security vulnerability has been detected in ChaiScript up to 6.1.0. This impacts the function chaiscript::eval::AST_Node_Impl::eval/chaiscript::eval::Function_Push_Pop of the file include/chaiscript/language/chaiscript_eval.hpp. The manipulation leads to uncontrolled recursion. An attack has to be approached locally. The exploit has been disclosed publicly and may be used. The project was informed of the problem early through an issue report but has not responded yet.

Impact

The primary impact of CVE-2026-3384 is denial of service through resource exhaustion caused by uncontrolled recursion in the ChaiScript interpreter. Organizations embedding ChaiScript in their applications or using it for local scripting could experience application crashes or degraded performance, potentially disrupting critical workflows or services. Since the attack requires local access and limited privileges, the threat is more relevant in environments where multiple users share access or where untrusted code execution is possible. Confidentiality and integrity impacts are minimal or nonexistent, but availability degradation can affect operational continuity. Systems relying heavily on ChaiScript for automation, configuration, or embedded scripting in industrial, IoT, or development environments are at higher risk. The lack of an official patch increases exposure time, and public exploit disclosure may lead to increased attempts to leverage this vulnerability.

Summary

CVE-2026-3384 identifies a vulnerability in the ChaiScript scripting engine, specifically affecting versions 6.0 and 6.1.0. The issue resides in the evaluation logic within the source file chaiscript_eval.hpp, notably in the functions chaiscript::eval::AST_Node_Impl::eval and chaiscript::eval::Function_Push_Pop. These functions handle the execution of abstract syntax tree nodes and function call stack management, respectively. The vulnerability manifests as uncontrolled recursion triggered by crafted input or script code, which causes the interpreter to enter a recursive loop without proper termination conditions. This uncontrolled recursion can lead to stack overflow or exhaustion of system resources, resulting in denial of service (DoS) conditions. The attack vector is local, requiring an attacker to have some level of local access and privileges to execute malicious scripts or inputs. No authentication bypass or remote exploitation is indicated. The CVSS 4.0 vector indicates low attack complexity, local attack vector, and limited privileges required, with no user interaction or confidentiality/integrity impact, culminating in a medium severity rating with a base score of 4.8. There are no known exploits in the wild yet, but public disclosure increases the risk of exploitation attempts.

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 9 Mar 2026, 01:20 UTC

Technical details

References

Community reviews

Related threats