VulnerabilityPublished 1 Mar 2026Updated 2 Mar 2026

CVE-2026-3389: Squirrel · NULL Pointer Dereference

Affects SquirrelSource CVE Database V5

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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
Squirrel	Affected =3.0 =3.1 =3.2	Fixed in–
GitHubalbertodemichelis/squirrel`pkg:github/albertodemichelis/squirrel`Other threats	Affected =3.0 =3.1 =3.2	Fixed in–

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

AI-suggested

Restrict local access to systems running Squirrel versions 3.0 to 3.2 to trusted users only, minimizing the risk of local exploitation.
Monitor applications embedding Squirrel for unexpected crashes or denial of service symptoms, enabling rapid detection of exploitation attempts.
Implement application-level input validation or sandboxing around scripting interfaces to prevent malformed inputs from reaching vulnerable code paths.
Where feasible, isolate or containerize applications using Squirrel to limit impact scope if a crash occurs.
Engage with the Squirrel project or community to track patch releases and apply updates promptly once available.
Consider upgrading to newer versions of Squirrel if they become available and address this vulnerability.
For critical environments, develop fallback or recovery procedures to quickly restore service after a crash.
Conduct internal audits to identify all systems using affected Squirrel versions to prioritize mitigation efforts.
Educate local users and administrators about the risk of local exploitation and enforce strict access controls.
If source code is available, consider temporary code fixes or workarounds to handle NULL pointers safely until official patches are released.

Description

A vulnerability was determined in Squirrel up to 3.2. This vulnerability affects the function sqstd_rex_newnode in the library sqstdlib/sqstdrex.cpp. Executing a manipulation can lead to null pointer dereference. The attack can only be executed locally. The exploit has been publicly disclosed and may be utilized. The project was informed of the problem early through an issue report but has not responded yet.

Impact

The primary impact of CVE-2026-3389 is denial of service due to application crashes caused by NULL pointer dereference. This can disrupt local services or software that embed the Squirrel scripting engine, potentially affecting stability and availability. For organizations relying on Squirrel in embedded devices, games, or automation tools, this could lead to operational interruptions or degraded user experience. Since exploitation requires local access, remote systems are less vulnerable unless an attacker gains local foothold first. The vulnerability does not compromise confidentiality or integrity, so data breaches or unauthorized modifications are unlikely. However, denial of service in critical embedded systems or local automation could have cascading effects, especially in industrial or IoT environments. The absence of a patch increases exposure time, and public disclosure raises the risk of future exploit development. Organizations worldwide using affected versions should consider the risk of local attackers causing service outages or instability.

Summary

CVE-2026-3389 identifies a NULL pointer dereference vulnerability in the Squirrel scripting language library, specifically in the sqstd_rex_newnode function located in sqstdlib/sqstdrex.cpp. This flaw arises when certain manipulated inputs cause the function to dereference a NULL pointer, leading to an application crash or denial of service. The vulnerability affects Squirrel versions 3.0, 3.1, and 3.2. Exploitation requires local access with limited privileges (PR:L) and no user interaction or authentication is needed beyond that. The attack vector is local (AV:L), and the attack complexity is low (AC:L), meaning an attacker with local access can reliably trigger the crash. The vulnerability impacts availability (VA:L) but does not affect confidentiality or integrity. The CVSS 4.0 base score is 4.8, reflecting medium severity. No known exploits are currently observed in the wild. The vulnerability primarily risks denial of service conditions in applications embedding or using Squirrel for scripting, potentially disrupting local services or software relying on it. Since Squirrel is often embedded in applications or games, the impact is mostly local and limited to affected systems. The lack of remote exploitation capability reduces the threat scope but local attackers or malicious insiders could leverage this to cause service interruptions.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 9 Mar 2026, 01:27 UTC

Technical details

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