VulnerabilityPublished 24 Sep 2025Updated 25 Sep 2025

CVE-2025-59305: Langfuse · Improper Authorization

Source CVE Database V5

Not known to be exploited · CVSS 7.6 High · fixed in 3.1 : patch affected systems soon.

Data as of 26 Oct 2026, 16:39 UTC

CVSS 3.1 base score

7.6High

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 20% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 3.1

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: Low
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: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
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: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on 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 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 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

AI-suggested

Immediate mitigation should include restricting access to the background migration endpoints to only highly trusted and necessary users or service accounts, implementing strict role-based access controls (RBAC) if not already in place.
Monitor and audit all calls to the background migration endpoints to detect any unauthorized or suspicious activity promptly.
If possible, disable or block access to these endpoints temporarily until a vendor patch or update is available.
Enforce strong authentication mechanisms and consider multi-factor authentication (MFA) to reduce the risk of compromised credentials being used to exploit this vulnerability.
Review and harden the application’s authorization logic to ensure that only users with explicit migration management privileges can invoke these functions.
Stay updated with Langfuse vendor advisories for patches or security updates addressing this issue and apply them promptly once released.
Conduct internal penetration testing or vulnerability assessments focusing on TRPC endpoints to identify any similar authorization weaknesses.

Description

Improper authorization in the background migration endpoints of Langfuse 3.1 before d67b317 allows any authenticated user to invoke migration control functions. This can lead to data corruption or denial of service through unauthorized access to TRPC endpoints such as backgroundMigrations.all, backgroundMigrations.status, and backgroundMigrations.retry.

Impact

For European organizations using Langfuse 3.1 or earlier versions before the specified commit, this vulnerability poses a substantial risk. Unauthorized invocation of migration controls can lead to data corruption, which may compromise the integrity of critical business data, analytics, or operational records. This can disrupt business processes, lead to incorrect decision-making, and potentially violate data protection regulations such as GDPR if personal or sensitive data is affected. Additionally, denial of service conditions caused by misuse of these endpoints can degrade system availability, impacting service continuity and user experience. Given that the vulnerability requires only authenticated access, insider threats or compromised user accounts could be leveraged to exploit this flaw. Organizations relying on Langfuse for data migration or analytics should be particularly cautious, as the disruption or corruption of migration processes can have cascading effects on data pipelines and dependent applications.

CWE-285Improper Authorization (opens in a new tab)
Class weaknessLikelihood of exploit: HighOWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design
Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) to enforce the roles at the appropriate boundaries.
Architecture and Design
Ensure that you perform access control checks related to your business logic. These checks may be different than the access control checks that you apply to more generic resources such as files, connections, processes, memory, and database records.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
OWASP Cheat Sheets
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.8 (opens in a new tab)
V13.4.2 (opens in a new tab)
V7.2.2 (opens in a new tab)
Attack patterns
Accessing Functionality Not Properly Constrained by ACLs (opens in a new tab)
Cross Zone Scripting (opens in a new tab)
Directory Indexing (opens in a new tab)
Subverting Environment Variable Values (opens in a new tab)
Using Malicious Files (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

depthfirst.com/post/how-an-authorization-flaw-reveals-a-common-security-blind-spot-cve-2025-59305-case-study (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 2 Oct 2025, 01:04 UTC

WeaknessesCWE-285

Technical details

References

Community reviews

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