VulnerabilityPublished 9 Feb 2026Updated 23 Feb 2026

CVE-2026-2242: janet · Out-of-bounds Read

Affects janetSource CVE Database V5

Public exploit available · CVSS 4.8 Medium.

Data as of 26 Oct 2026, 12:55 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 7% 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 9 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 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

Affected software

Product	Affected	Fixed in
janet-langjanet	Affected =1.40.0 =1.40.1	Fixed in–

AI-suggested

To mitigate CVE-2026-2242, organizations should promptly apply the official patch identified by commit c43e06672cd9dacf2122c99f362120a17c34b391 that corrects the bounds checking in the janetc_if function. If patching is not immediately feasible, restrict local access to systems running janet-lang to trusted users only, minimizing the risk of exploitation. Employ strict access controls and monitoring to detect unusual local activity. Consider running janet-lang processes with least privilege and in isolated environments or containers to limit impact of potential exploitation. Regularly audit and update janet-lang versions to incorporate security fixes. Additionally, review usage of janet-lang in production to assess whether alternative scripting environments with broader security support might be appropriate. Implement host-based intrusion detection to alert on suspicious local behavior targeting janet-lang processes.

Description

A vulnerability was determined in janet-lang janet up to 1.40.1. This impacts the function janetc_if of the file src/core/specials.c. Executing a manipulation can lead to out-of-bounds read. The attack needs to be launched locally. The exploit has been publicly disclosed and may be utilized. This patch is called c43e06672cd9dacf2122c99f362120a17c34b391. It is advisable to implement a patch to correct this issue.

Impact

The primary impact of CVE-2026-2242 is potential information disclosure due to out-of-bounds memory reads. While it does not directly allow code execution or privilege escalation, the vulnerability could enable attackers to access sensitive data residing in adjacent memory regions, which may include secrets, pointers, or other critical runtime information. This could facilitate further attacks or reconnaissance within a compromised system. Additionally, the out-of-bounds read could cause application instability or crashes, impacting availability of services relying on janet-lang. Since exploitation requires local access, the threat is mainly to environments where untrusted users have local accounts or where multi-tenant systems run janet-lang scripts. Organizations using janet-lang in development, testing, or production should consider the risk of insider threats or compromised local accounts. The medium severity rating reflects moderate risk, but the actual impact depends on deployment context and sensitivity of data processed by janet-lang scripts.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 23 Feb 2026, 21:13 UTC

Technical details

References

Community reviews

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