CVE-2026-2661VulnerabilityPublished 18 Feb 2026Updated 23 Feb 2026

CVE-2026-2661: Squirrel · Heap-based Buffer Overflow

Affects SquirrelSource CVE Database V5

Not known to be exploited · CVSS 4.8 Medium.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 4.0 base score

4.8Medium

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 18% 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 18 Feb 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 2026-10-26.

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 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–

AI-suggested

1. Restrict local access to systems running vulnerable Squirrel versions by enforcing strict user permissions and limiting physical and remote console access. 2. Employ application sandboxing or containerization to isolate processes using Squirrel, reducing the impact of potential exploitation. 3. Monitor system and application logs for abnormal behavior or crashes related to Squirrel processes to detect exploitation attempts early. 4. If feasible, replace or upgrade the Squirrel engine to a version not affected by this vulnerability once a patch is released or consider alternative scripting engines with active maintenance. 5. Conduct regular security audits and vulnerability scans focusing on local privilege escalation vectors. 6. Apply host-based intrusion detection systems (HIDS) to detect anomalous memory or process behavior indicative of heap overflow exploitation. 7. Educate users and administrators about the risks of local exploitation and enforce strong authentication and session management to reduce unauthorized local access. 8. Engage with the Squirrel project or community to track patch releases and apply updates promptly once available.

Description

A security flaw has been discovered in Squirrel up to 3.2. This affects the function SQObjectPtr::operator in the library squirrel/sqobject.h. The manipulation results in heap-based buffer overflow. The attack needs to be approached locally. The exploit has been released to the public and may be used for attacks. The project was informed of the problem early through an issue report but has not responded yet.

Impact

The primary impact of CVE-2026-2661 is potential arbitrary code execution or application crashes due to heap memory corruption. For organizations, this could lead to local privilege escalation if attackers gain low-level access and exploit the overflow to execute malicious code with the privileges of the vulnerable process. This could compromise system integrity and confidentiality if the affected application handles sensitive data or controls critical functions. Availability may also be affected if the overflow causes application or system crashes. Since exploitation requires local access, remote attackers cannot directly exploit this vulnerability without first gaining a foothold. However, in environments where Squirrel is embedded in client software or devices, attackers with local access (e.g., via compromised user accounts or physical access) could leverage this flaw to escalate privileges or persist. The public release of exploit code increases the likelihood of opportunistic attacks, especially in environments with weak local security controls. Lack of an official patch means organizations must rely on mitigations and monitoring until a fix is available.

Summary

CVE-2026-2661 identifies a heap-based buffer overflow vulnerability in the Squirrel scripting language library, affecting versions 3.0, 3.1, and 3.2. The vulnerability resides in the SQObjectPtr::operator function defined in squirrel/sqobject.h, where improper handling of data leads to an overflow on the heap. Heap-based overflows can corrupt adjacent memory, potentially allowing attackers to overwrite critical data structures or control flow information. Exploitation requires local access with low privileges and does not require user interaction, making it a local privilege escalation or code execution vector if combined with other vulnerabilities or misconfigurations. The vulnerability was responsibly disclosed but remains unpatched as of the publication date, and exploit code has been publicly released, increasing the risk of exploitation. The CVSS 4.0 base score is 4.8, reflecting medium severity due to the local attack vector and limited scope. No known exploits in the wild have been reported, but the availability of proof-of-concept code raises the threat level. The vulnerability impacts any software or systems embedding or using the Squirrel scripting engine in the affected versions, which is commonly used in embedded systems, games, and applications requiring lightweight scripting.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 28 Feb 2026, 13:36 UTC

Technical details

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