CVE-2025-14957VulnerabilityPublished 19 Dec 2025Updated 24 Feb 2026

CVE-2025-14957: WebAssembly Binaryen · NULL Pointer Dereference

Affects WebAssembly BinaryenSource CVE Database V5

Not known to be exploited · CVSS 4.8 Medium.

Data as of 25 Oct 2026, 19:02 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 11% 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 19 Dec 2025
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 2026-10-25.

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
GitHubwebassembly/binaryen`pkg:github/webassembly/binaryen`Other threats	Affected =125	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-2025-14957, organizations should immediately apply the official patch identified by commit 6fb2b917a79578ab44cf3b900a6da4c27251e0d4 to update Binaryen to a fixed version beyond 125. Development and build environments should enforce strict access controls to limit local access to trusted users only, reducing the risk of exploitation. Implement monitoring for abnormal crashes or failures in WebAssembly compilation processes to detect potential exploitation attempts. Incorporate Binaryen updates into regular software supply chain management and continuous integration pipelines to ensure timely patching. If patching is temporarily not possible, consider isolating build environments or using containerization to limit the impact of crashes. Educate developers and system administrators about the vulnerability and the importance of applying updates promptly. Finally, review and harden local user permissions and audit logs to detect unauthorized access that could lead to exploitation.

Description

A vulnerability was identified in WebAssembly Binaryen up to 125. This affects the function IRBuilder::makeLocalGet/IRBuilder::makeLocalSet/IRBuilder::makeLocalTee of the file src/wasm/wasm-ir-builder.cpp of the component IRBuilder. Such manipulation of the argument Index leads to null pointer dereference. Local access is required to approach this attack. The exploit is publicly available and might be used. The name of the patch is 6fb2b917a79578ab44cf3b900a6da4c27251e0d4. Applying a patch is advised to resolve this issue.

Impact

The primary impact of CVE-2025-14957 is denial of service through application crashes caused by NULL pointer dereference. This can disrupt development workflows, continuous integration pipelines, or runtime environments that rely on Binaryen for WebAssembly code generation or optimization. While the vulnerability does not allow remote exploitation or privilege escalation, it can cause instability in local environments, potentially halting build processes or automated deployments. Organizations relying on WebAssembly for critical applications or services may experience interruptions or delays. Since exploitation requires local access, the risk is higher in multi-user systems, shared development environments, or compromised hosts where an attacker has gained limited access. The availability of a public exploit increases the risk of opportunistic attacks, especially in environments where patching is delayed. However, the vulnerability does not directly expose sensitive data or allow code execution beyond crashing the process.

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 24 Feb 2026, 23:07 UTC

Technical details

References

Community reviews

Related threats