Auth bypass in Nessshon Tonapi
CVE-2026-54635
pytonapi is a Python SDK for TONAPI that provides REST API, streaming, and webhook access to the TON blockchain. From 2.0.0 to 2.2.0, TonapiWebhookDispatcher fails to validate the Authorization header when a webhook handler is registered with the documented path argument, because setup() stores bearer tokens only under the default suffix paths and never adds the custom path to the token map, so self._tokens.get(path) returns None and the authentication guard is skipped. An unauthenticated remote attacker can POST forged payloads to the custom webhook endpoint and trigger victim-defined handlers. This issue is fixed in version 2.2.1.
Vulnerability class: Broken Authentication
EPSS: 0.004 (35.4th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.
Affected products
- Nessshon Tonapi — versions >= 2.0.0, < 2.2.1
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-54635?
- CVE-2026-54635 is a high-severity vulnerability in Nessshon Tonapi, classified under Improper Authentication. CVSS score: 7.5/10. Published 2026-07-28.
- How severe is CVE-2026-54635?
- High severity. CVSS v3 base score is 7.5 out of 10.