CVE-2026-41644 — monetr
Fix: monetr/monetr@c260caaCVE-2026-41644 is a CWE-209 vulnerability in github.com/monetr/monetr. A fix is available for github.com/monetr/monetr — see the affected versions and patch details below.
monetr is vulnerable to server-side request forgery in Lunch Flow link creation and refresh
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-41644.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
github.com/monetr/monetrReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
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=falseso 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: falsein 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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/monetr/monetr | all versions | 1.12.5go get github.com/monetr/monetr@v1.12.5 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/monetr/monetr, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/monetr/monetr to 1.12.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-41644 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-41644 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-41644. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-41644 in your dependencies?
O3 Security finds CVE-2026-41644 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.