VulnerabilityPublished 26 Apr 2024Updated 21 Nov 2024

CVE-2024-33263: JSRuntime *

Source CVE Database V5

Not known to be exploited · CVSS 4.0 Medium.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score

4.0Medium

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

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

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

Attack Vector: Local: The vulnerable component 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 remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
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: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within 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 26 Apr 2024
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

AI-suggested

To mitigate CVE-2024-33263, organizations should first monitor official QuickJS repositories and security advisories for patches addressing this assertion failure and apply them promptly once available. In the interim, restricting local access to systems running QuickJS can reduce the risk of exploitation. Employing runtime monitoring and watchdog mechanisms to detect and recover from unexpected QuickJS crashes can help maintain service availability. Developers embedding QuickJS should implement input validation and sandboxing to limit the execution of untrusted or malformed JavaScript code that might trigger the assertion failure. Additionally, consider isolating QuickJS instances in containerized or virtualized environments to contain potential crashes. Regularly auditing and updating embedded JavaScript engines and their dependencies is critical to minimize exposure to such vulnerabilities. Finally, incident response plans should include procedures for handling denial-of-service conditions caused by runtime crashes.

Description

QuickJS commit 3b45d15 was discovered to contain an Assertion Failure via JS_FreeRuntime(JSRuntime *) at quickjs.c.

Impact

The primary impact of CVE-2024-33263 is a denial-of-service condition that can disrupt applications or devices embedding QuickJS by crashing the JavaScript runtime. This can lead to service interruptions, reduced availability, and potential operational downtime in affected systems. Since the attack requires local access, remote exploitation is unlikely without prior compromise. However, in environments where QuickJS is embedded in critical infrastructure, IoT devices, or edge computing platforms, an attacker with local access could leverage this vulnerability to cause instability or outages. The lack of impact on confidentiality and integrity limits the risk to data breaches or unauthorized modifications. Nevertheless, availability disruptions can have cascading effects, especially in industrial, telecommunications, or embedded device contexts where QuickJS is used. Organizations relying on QuickJS should consider the operational risks of runtime crashes and the potential for attackers to exploit this flaw to degrade service reliability.

References

github.com/bellard/quickjs/issues/277 (opens in a new tab)

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