VulnerabilityPublished 22 Dec 2025

CVE-2025-68480: marshmallow · Asymmetric Resource Consumption

Affects marshmallowSource CVE Database V5

Not known to be exploited · CVSS 5.3 Medium : upgrade to 4.1.2 when convenient.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score

5.3Medium

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 22% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 4.1.2

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

Attack Vector: Network
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: 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: 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 22 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 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

Upgrade marshmallow to 4.1.2.

Affected software

Product	Affected	Fixed in
PyPImarshmallow`pkg:pypi/marshmallow`Other threats	Affected >=4.0.0 <4.1.2	Fixed in 4.1.2

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

AI-suggested

The most effective mitigation is to upgrade all instances of the marshmallow library to version 3.26.2 or 4.1.2 and later, where the vulnerability is patched. Organizations should conduct an inventory of Python applications and dependencies to identify vulnerable versions. In addition to upgrading, developers should implement strict input validation to reject malformed or unexpected data before deserialization. Rate limiting and throttling mechanisms at the application or API gateway level can reduce the risk of resource exhaustion from repeated malicious requests. Monitoring CPU usage and application performance metrics can help detect anomalous behavior indicative of exploitation attempts. For critical systems, consider isolating services using marshmallow in containerized or sandboxed environments to limit the impact of potential DoS attacks. Finally, maintain an up-to-date patch management process and subscribe to vulnerability advisories related to Python libraries to respond promptly to future issues.

Description

Marshmallow is a lightweight library for converting complex objects to and from simple Python datatypes. In versions from 3.0.0rc1 to before 3.26.2 and from 4.0.0 to before 4.1.2, Schema.load(data, many=True) is vulnerable to denial of service attacks. A moderately sized request can consume a disproportionate amount of CPU time. This issue has been patched in version 3.26.2 and 4.1.2.

Impact

For European organizations, the primary impact of CVE-2025-68480 is the risk of denial of service attacks against applications that utilize vulnerable versions of the marshmallow library for data deserialization. This can lead to application downtime, degraded user experience, and potential disruption of critical services, especially for web-facing applications or APIs that accept untrusted input. Organizations in sectors such as finance, healthcare, government, and technology, which often rely on Python-based services, may face operational risks and reputational damage if exploited. Additionally, the increased CPU consumption could lead to higher infrastructure costs and complicate incident response efforts. While the vulnerability does not expose sensitive data or allow unauthorized data modification, the availability impact alone can have significant business consequences. European companies with compliance obligations around service availability and incident management (e.g., under GDPR or sector-specific regulations) must prioritize addressing this vulnerability to avoid regulatory scrutiny and potential penalties.

CWE-405Asymmetric Resource Consumption (Amplification) (opens in a new tab)
Class weakness
The product does not properly control situations in which an adversary can cause the product to consume or produce excessive resources without requiring the adversary to invest equivalent work or otherwise prove authorization, i.e., the adversary's influence is "asymmetric."
Architecture and Design
An application must make resources available to a client commensurate with the client's access level.
Architecture and Design
An application must, at all times, keep track of allocated resources and meter their usage appropriately.
System Configuration
Consider disabling resource-intensive algorithms on the server side, such as Diffie-Hellman key exchange.
OWASP Cheat Sheets
File Upload (opens in a new tab)
OWASP ASVS 4.0.3
V12.1.1 (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

Affected software

Description

AI analysisMachine-generated, updated 22 Dec 2025, 22:14 UTC

WeaknessesCWE-405

Technical details

References

Community reviews

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