CVE-2026-35628: OpenClaw < 2026.3.25 - Brute-Force Attack via Missing Telegram Webhook Rate Limiting

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-04-09 · updated 2026-06-17
Weakness: CWE-307

Description

OpenClaw before 2026.3.25 contains a missing rate limiting vulnerability in Telegram webhook authentication that allows attackers to brute-force weak webhook secrets. The vulnerability enables repeated authentication guesses without throttling, permitting attackers to systematically guess webhook secrets through brute-force attacks.

Affected products

OpenClaw: before 2026.3.25 — fixed in 2026.3.25

How to fix

Upgrade to a fixed version: OpenClaw 2026.3.25. Check the vendor advisory for mitigations.

References

https://github.com/openclaw/openclaw/commit/c2c136ae9517ddd0789d742a0fdf4c10e8c729a7
https://github.com/openclaw/openclaw/security/advisories/GHSA-vcx4-4qxg-mfp4
https://www.vulncheck.com/advisories/openclaw-brute-force-attack-via-missing-telegram-webhook-rate-limiting

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