VulnerabilityPublished 24 Sep 2025Updated 25 Sep 2025

CVE-2025-57318: A Prototype Pollution

Source CVE Database V5

Not known to be exploited · CVSS 7.5 High.

Data as of 26 Oct 2026, 09:08 UTC

CVSS 3.1 base score

7.5High

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 33% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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

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

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
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: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 24 Sep 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 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 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 this vulnerability, European organizations should first identify all instances where csvjson versions up to 5.1.0 are used, particularly focusing on the toCsv function. Immediate steps include: 1) Applying any available patches or updates from the csvjson maintainers once released. 2) If patches are not yet available, implement input validation and sanitization to prevent malicious payloads from reaching the toCsv function. 3) Employ runtime protections such as limiting resource consumption and monitoring for unusual application behavior indicative of prototype pollution exploitation. 4) Consider using alternative libraries or custom CSV serialization methods that do not suffer from prototype pollution vulnerabilities. 5) Conduct thorough code reviews and security testing focusing on prototype pollution vectors. 6) Deploy Web Application Firewalls (WAFs) with rules to detect and block suspicious payloads targeting prototype pollution. 7) Maintain an incident response plan to quickly address potential DoS incidents caused by exploitation attempts. These measures, combined with continuous monitoring and threat intelligence updates, will help reduce the risk and impact of this vulnerability.

Description

A Prototype Pollution vulnerability in the toCsv function of csvjson versions thru 5.1.0 allows attackers to inject properties on Object.prototype via supplying a crafted payload, causing denial of service (DoS) as the minimum consequence.

Impact

For European organizations, the impact of this vulnerability can be substantial, especially those that utilize the csvjson library in their software stacks for data processing or transformation tasks. The denial of service caused by prototype pollution can disrupt critical business operations, leading to downtime and potential loss of productivity. Since the vulnerability does not require authentication or user interaction, it can be exploited remotely, increasing the risk of automated attacks or exploitation by malicious actors scanning for vulnerable endpoints. Organizations in sectors such as finance, healthcare, and public services, which often handle large volumes of CSV data and rely on stable backend services, may face operational disruptions. Additionally, if the affected applications are part of larger supply chains or cloud services, the ripple effect could impact multiple dependent systems. Although confidentiality and integrity are not directly compromised, the availability impact alone can lead to regulatory scrutiny under European data protection laws like GDPR if service interruptions affect data processing obligations or user access.

CWE-1321Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') (opens in a new tab)
Variant weakness
The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.
Implementation
By freezing the object prototype first (for example, Object.freeze(Object.prototype)), modification of the prototype becomes impossible.
Architecture and Design
By blocking modifications of attributes that resolve to object prototype, such as proto or prototype, this weakness can be mitigated.
Implementation · Input Validation
When handling untrusted objects, validating using a schema can be used.
OWASP Cheat Sheets
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V5.1.2 (opens in a new tab)
Attack patterns
Accessing Functionality Not Properly Constrained by ACLs (opens in a new tab)
Exploiting Incorrectly Configured Access Control Security Levels (opens in a new tab)
Manipulating User-Controlled Variables (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 2 Oct 2025, 01:06 UTC

WeaknessesCWE-1321

Technical details

References

Community reviews

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