VulnerabilityPublished 22 Apr 2026Updated 8 May 2026

CVE-2026-41644: monetr · Server-side request forgery in Lunch Flow link creation and refresh

Affects github.com/monetr/monetrSource GCVE Database

Authoritative record:CVE-2026-41644· High 8.3

Not known to be exploited · CVSS 8.3 High : upgrade to 1.12.5 soon.

Data as of 27 Oct 2026, 00:07 UTC

CVSS 4.0 base score

8.3High

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

Patch: Available – fixed in 1.12.5

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:L/SC:H/SI:N/SA:N

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: Low
User Interaction: None
Vulnerable system confidentiality: High
Vulnerable system integrity: None
Vulnerable system availability: Low
Subsequent system confidentiality: High
Subsequent system integrity: None
Subsequent system availability: None

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

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, 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: 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: High: There is a total loss of confidentiality, resulting in all information within the Vulnerable System being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
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: High: There is a total loss of confidentiality, resulting in all resources within the Subsequent System being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
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.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 7 May 2026
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 github.com/monetr/monetr to 1.12.5.

Affected software

Product	Affected	Fixed in
Gogithub.com/monetr/monetr	Affected <1.12.5	Fixed in 1.12.5

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

Description

### Impact A server-side request forgery (SSRF) vulnerability in monetr's Lunch Flow integration allowed any authenticated user on a self-hosted instance to cause the monetr server to issue HTTP GET requests to arbitrary URLs supplied by the caller, with the response body from non-200 upstream responses reflected back in the API error message. The URL validator on `POST /api/lunch_flow/link` only checked the URL scheme and rejected query parameters; it did not filter loopback, RFC1918, link-local, or cloud-provider metadata addresses. The outbound HTTP client read the response body via an unbounded `io.ReadAll`, and the controller intentionally surfaced the resulting error (which contained the upstream body) as the JSON `error` field of the API response. **Who is affected:** self-hosted monetr deployments running the default configuration. Out of the box, `LunchFlow.Enabled=true`, `AllowSignUp=true`, and billing is not enforced, so any user who can register on the instance can reach the vulnerable endpoint. Deployments running in a cloud environment where instance metadata is reachable from the pod (e.g. AWS EC2 without IMDSv2 enforced) expand the impact to include potential exposure of instance metadata through the reflected error body. **Who is NOT affected:** the hosted `my.monetr.app` service, which runs with `LunchFlow.Enabled=false`. Self-hosted operators who had already disabled public sign-up (`MONETR_ALLOW_SIGN_UP=false`) substantially reduce their exposure since only operator-trusted users can reach the endpoint. A secondary denial-of-service vector also existed: because the outbound response body was read with no size cap, an attacker-influenced upstream could return a multi-GB body that monetr would fully buffer into memory. ### Patches Fixed in monetr `v1.12.5`. Users should upgrade to this release or later. The fix introduces a new config field `LunchFlow.AllowedApiUrls` (a list of permitted Lunch Flow API URLs) with a default of `["https://lunchflow.app/api/v1"]`. URLs outside the allowlist are rejected both at link-creation time and at client-construction time, with a server-side warning log on rejection. Response body reads are capped at 10 MiB for both success and error paths. The UI renders the API URL field as a disabled pre-filled input when a single URL is allowed, or a dropdown when multiple are allowed, so operators who need to use a staging or self-hosted Lunch Flow API opt in explicitly via config. **Upgrade note for self-hosters with a custom Lunch Flow URL:** if your existing `LunchFlowLink` records point at a URL other than `https://lunchflow.app/api/v1`, set your `lunchFlow.allowedApiUrls` in your yaml config to include your custom URL before upgrading. Otherwise existing links will fail on next refresh or sync with a `"Rejected Lunch Flow API URL that is not in the configured allowlist"` warning in the server log. ### Workarounds For operators who cannot upgrade immediately, any of the following materially reduces or eliminates exposure: - **Disable public sign-up:** set `MONETR_ALLOW_SIGN_UP=false` so only operator-trusted users can reach the vulnerable endpoint. Recommended in general for internet-exposed self-hosted deployments. - **Disable Lunch Flow entirely:** set `lunchFlow.enabled: false` in your config file. The endpoints will return 404 for all callers. - **Network-level egress restriction:** restrict outbound HTTP egress from the monetr pod/container to only `lunchflow.app` (or whichever legitimate Lunch Flow hosts you use). Blocks the SSRF primitive regardless of application-layer validation. - **On AWS EC2 specifically:** enforce IMDSv2 on the instance. This eliminates the cloud-metadata exfil path even if the SSRF primitive remains reachable.

CWE-209Generation of Error Message Containing Sensitive Information (opens in a new tab)
Base weaknessLikelihood of exploit: HighOWASP Top 10 A10:2025: Mishandling of Exceptional Conditions (opens in a new tab)
The product generates an error message that includes sensitive information about its environment, users, or associated data.
Implementation
Ensure that error messages only contain minimal details that are useful to the intended audience and no one else. The messages need to strike the balance between being too cryptic (which can confuse users) or being too detailed (which may reveal more than intended).
Implementation
Handle exceptions internally and do not display errors containing potentially sensitive information to a user.
Implementation · Attack Surface Reduction
Use naming conventions and strong types to make it easier to spot when sensitive data is being used. When creating structures, objects, or other complex entities, separate the sensitive and non-sensitive data as much as possible.
OWASP Cheat Sheets
Error Handling (opens in a new tab)
Logging (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.4 (opens in a new tab)
V14.3.3 (opens in a new tab)
V7.3.3 (opens in a new tab)
Attack patterns
Fuzzing for application mapping (opens in a new tab)
Padding Oracle Crypto Attack (opens in a new tab)
Query System for Information (opens in a new tab)
Blind SQL Injection (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-770Allocation of Resources Without Limits or Throttling (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #25
The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.
Requirements
Clearly specify the minimum and maximum expectations for capabilities, and dictate which behaviors are acceptable when resource allocation reaches limits.
Architecture and Design
Limit the amount of resources that are accessible to unprivileged users. Set per-user limits for resources. Allow the system administrator to define these limits. Be careful to avoid CWE-410.
Architecture and Design
Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended.
OWASP Cheat Sheets
Abuse Case (opens in a new tab)
OWASP ASVS 4.0.3
V8.1.4 (opens in a new tab)
V13.4.1 (opens in a new tab)
V11.1.4 (opens in a new tab)
Attack patterns
XML Ping of the Death (opens in a new tab)
Exponential Data Expansion (opens in a new tab)
Serialized Data Parameter Blowup (opens in a new tab)
Serialized Data with Nested Payloads (opens in a new tab)
Oversized Serialized Data Payloads (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-918Server-Side Request Forgery (SSRF) (opens in a new tab)
Base weaknessCWE Top 25 (2025): #22OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.
OWASP Cheat Sheets
Server Side Request Forgery Prevention (opens in a new tab)
Unvalidated Redirects and Forwards (opens in a new tab)
Cross Site Scripting Prevention (opens in a new tab)
DOM based XSS Prevention (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V12.6.1 (opens in a new tab)
V5.2.6 (opens in a new tab)
Attack patterns
Server Side Request Forgery (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

WeaknessesCWE-209, CWE-770, CWE-918

Technical details

References

Community reviews

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