CVE-2025-7338VulnerabilityPublished 17 Jul 2025

CVE-2025-7338: expressjs multer · CWE-248

Affects expressjs multerSource CVE Database V5

Not known to be exploited · CVSS 7.5 High : upgrade to 2.0.2 soon.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

7.5High

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

EPSS: 0.8% chance of exploitation in 30 days – higher than 56% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 2.0.2

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 17 Jul 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

Upgrade expressjs multer to 2.0.2.

Affected software

Product	Affected	Fixed in
npmmulter`pkg:npm/multer`Other threats	Affected =1.4.4-lts.1 <2.0.2	Fixed in 2.0.2

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

1. Immediate upgrade of Multer to version 2.0.2 or later is the most effective mitigation. This patch addresses the unhandled exception and prevents the DoS condition. 2. Implement input validation and sanitization at the application level to detect and reject malformed multipart requests before they reach Multer. 3. Deploy Web Application Firewalls (WAFs) with rules to detect and block anomalous multipart/form-data payloads that deviate from expected formats. 4. Introduce rate limiting and connection throttling on endpoints handling file uploads to reduce the risk of DoS attacks. 5. Monitor application logs and server health metrics closely for signs of crashes or abnormal request patterns indicative of exploitation attempts. 6. Consider isolating file upload handling in separate processes or containers to limit the blast radius of a crash. 7. Conduct security testing and fuzzing of multipart upload functionality to identify and remediate other potential parsing issues. 8. Maintain an incident response plan to quickly recover from potential DoS incidents, including automated restarts and failover mechanisms.

Description

Multer is a node.js middleware for handling `multipart/form-data`. A vulnerability that is present starting in version 1.4.4-lts.1 and prior to version 2.0.2 allows an attacker to trigger a Denial of Service (DoS) by sending a malformed multi-part upload request. This request causes an unhandled exception, leading to a crash of the process. Users should upgrade to version 2.0.2 to receive a patch. No known workarounds are available.

Impact

For European organizations, this vulnerability can have considerable operational impact, especially for businesses and services that rely heavily on Node.js and Express.js frameworks with Multer middleware for file upload functionality. Industries such as e-commerce, healthcare, finance, and public sector services that provide web portals for document uploads or user-generated content are particularly at risk. A successful DoS attack could lead to service outages, loss of customer trust, potential regulatory scrutiny under GDPR due to service disruption, and financial losses from downtime. Since the vulnerability allows remote exploitation without authentication, attackers can easily target exposed endpoints. This risk is amplified for organizations with internet-facing applications that do not have additional protective layers such as Web Application Firewalls (WAFs) or rate limiting. The lack of known exploits in the wild currently provides a window for proactive mitigation, but the high CVSS score (7.5) indicates that the threat could be weaponized quickly once exploit code becomes available.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 17 Jul 2025, 17:16 UTC

WeaknessesCWE-248

Technical details

References

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