6.9
MEDIUM CVSS 4.0
CVE-2026-56331
Capgo - Improper Error Handling in Accept Invitation Endpoint via Invalid Magic String
Description

Capgo before 12.128.2 contains improper error handling in the /private/accept_invitation endpoint that returns HTTP 500 instead of safe 4xx errors when magic_invite_string is invalid. Attackers can trigger this vulnerability using only the public key by submitting malformed magic_invite_string values to cause server errors and leak internal processing details.

INFO

Published Date :

June 30, 2026, 11:17 p.m.

Last Modified :

July 1, 2026, 4:16 p.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2026-56331 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Capgo capgo
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 134c704f-9b21-4f2e-91b3-4a467353bcc0
CVSS 3.1 MEDIUM 83251b91-4cc7-4094-a5c7-464a1b83ea10
CVSS 3.1 MEDIUM [email protected]
CVSS 4.0 MEDIUM 83251b91-4cc7-4094-a5c7-464a1b83ea10
CVSS 4.0 MEDIUM [email protected]
Solution
Update Capgo to a version that addresses improper error handling in the accept invitation endpoint.
  • Update Capgo to version 12.128.2 or later.
  • Ensure the accept_invitation endpoint handles invalid input securely.
  • Validate all input parameters before processing.
References to Advisories, Solutions, and Tools
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-56331 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-56331 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-56331 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-56331 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Jul. 01, 2026

    Action Type Old Value New Value
    Added Reference https://github.com/Cap-go/capgo/security/advisories/GHSA-34p8-fh3m-376x
    Added SSVC {'id': 'CVE-2026-56331', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-01T14:42:08.528073Z'}
  • New CVE Received by [email protected]

    Jun. 30, 2026

    Action Type Old Value New Value
    Added Affected [{'vendor': 'Capgo', 'product': 'Capgo', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '12.128.2', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '12.128.2', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}]
    Added Description Capgo before 12.128.2 contains improper error handling in the /private/accept_invitation endpoint that returns HTTP 500 instead of safe 4xx errors when magic_invite_string is invalid. Attackers can trigger this vulnerability using only the public key by submitting malformed magic_invite_string values to cause server errors and leak internal processing details.
    Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/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
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
    Added CWE CWE-209
    Added Reference https://github.com/Cap-go/capgo/security/advisories/GHSA-34p8-fh3m-376x
    Added Reference https://www.vulncheck.com/advisories/capgo-improper-error-handling-in-accept-invitation-endpoint-via-invalid-magic-string
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.