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Fencer Intel
high 7.5

CVE-2026-40481 json

monetr: Unauthenticated Stripe webhook reads attacker-sized request bodies before signature validation

published 6mo ago modified 4mo ago also GHSA-v7xq-3wx6-fqc2 , GO-2026-5654 , EUVD-2026-23591

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 39%
public exploits
0
none known

Summary

monetr is a budgeting application for recurring expenses. In versions 1.12.3 and below, the public Stripe webhook endpoint buffers the entire request body into memory before validating the Stripe signature. A remote unauthenticated attacker can send oversized POST payloads to cause uncontrolled memory growth, leading to denial of service. The issue affects deployments with Stripe webhooks enabled and is mitigated if an upstream proxy enforces a request body size limit. This issue has been fixed in version 1.12.4.

Patch / fix

  • go github.com/monetr/monetr 1.12.4
  • monetr monetr 1.12.4
  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

Is CVE-2026-40481 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
6mo ago

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/monetr/monetr/security/advisories/GHSA-v7xq-3wx6-fqc2 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 8.2 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CNA 4.0 8.2 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
go github.com/monetr/monetr
<1.12.4
1.12.4

Affected products

  • monetr monetr

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption
  • CWE-770 Allocation of Resources Without Limits or Throttling

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.