EUVD-2026-87479
GHSA-gcvj-pm5f-x5cv
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V2 - Validation and Business Logic Resource consumption limits
MITRE ATT&CK
1 technique across 1 tactic: Impact The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | This is a genuinely low-priority availability issue despite the moderate 6.9 CVSS 4.0 score. The vendor vector (AV:N/AC:L/PR:N/UI:N/VC:N/VI:N/VA:L) correctly encodes the reality: network-reachable and unauthenticated, but the ONLY impact is partial, temporary availability (VA:L) - no confidentiality or integrity loss. The description explicitly confirms the attacker cannot obtain a valid token or read message data. No EPSS score, no CISA KEV listing, and no public POC were provided, so there is no signal of active or likely exploitation. The 6.9 score is somewhat inflated relative to real risk because the outcome is merely that legitimate Synology Chat webhook callbacks are rejected until the rate-limit window expires - a self-healing, channel-scoped nuisance, not a service-wide outage. The PR:N/AC:L rating is technically defensible but understates a real gating factor: exploitation only works in deployments where OpenClaw sits behind a trusted reverse proxy/tunnel that collapses many external clients onto one socket address. In a direct-exposure deployment the per-socket keying would isolate the attacker to their own budget. Bottom line: real but minor, not a patch-tonight emergency. |
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Alert meAnalysisAIv1 – Sep 26, 2026
Unauthenticated senders can temporarily disable OpenClaw's Synology Chat webhook integration by exhausting a shared invalid-token rate-limit budget on versions 2026.3.25 through 2026.8.1. Because the limiter is applied before authentication and keyed on the raw proxy socket address, any deployment where OpenClaw sits behind a reverse proxy or tunnel causes all external clients to share one counter, so junk webhook calls from a single source can cause legitimate Synology Chat callbacks to be rejected until the rate-limit window resets. The attacker gains no token and no message data - this is a scoped, temporary availability loss (CVSS 4.0 base 6.9, AV:N/PR:N/VA:L) with no public exploit identified at time of analysis, and it is assessed as a genuinely low-priority DoS issue; the vendor-released fix is 2026.8.1.
RemediationAI
Upgrade to OpenClaw 2026.8.1 or later, which is the vendor-released fix for this issue; see the GitHub advisory at https://github.com/openclaw/openclaw/security/advisories/GHSA-fw6q-2frm-jxxr and the VulnCheck advisory at https://www.vulncheck.com/advisories/openclaw-before-2026.8.1-denial-of-service-via-rate-limit for upgrade guidance. Where an immediate upgrade is not possible, the most effective compensating control is to stop untrusted clients from reaching the webhook route at all: restrict inbound access to the Synology Chat webhook path at the reverse proxy, tunnel or edge firewall so that only Synology's published callback source ranges can connect - the trade-off is that any change to those ranges will silently break callbacks until the allowlist is updated. If OpenClaw can be configured to derive the rate-limit key from a trusted forwarded client address (for example via a proxy-protocol or X-Forwarded-For header that only the trusted proxy may set), doing so restores per-client budgets; this must only be enabled when the proxy strips client-supplied versions of those headers, otherwise the limiter becomes trivially spoofable and offers no protection. Raising the invalid-token threshold or shortening the rate-limit window reduces the duration of legitimate-callback rejection but proportionally weakens the abuse protection the limiter was intended to provide, and is therefore only a stopgap. Because exploitation yields no credential or data disclosure, emergency patching is not warranted - treat this as a scheduled maintenance upgrade, prioritize internet-facing or multi-tenant proxy-fronted instances first, and monitor webhook rejection rates as a detection signal for both attacks and allowlist misconfiguration.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in euvd
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
OpenClaw exposes a webhook endpoint that accepts inbound callbacks from Synology Chat. Before validating an incoming request's token, the code path applies invalid-token rate limiting, and the limiter's key is the raw peer socket address rather than an authenticated identity or a forwarded client address. This is a CWE-400 uncontrolled resource consumption pattern: a security control that consumes a finite shared budget is placed in front of authentication, and its granularity is coarser than the trust boundary it protects. In typical production topologies OpenClaw is fronted by a trusted reverse proxy or tunnel, so the socket address the application observes is the proxy's address; every external Synology Chat client therefore maps to one rate-limit bucket. An unauthenticated party that can reach the webhook route can fill that bucket with requests carrying invalid tokens, after which the limiter rejects all further callbacks - including legitimate ones - for the duration of the window. The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N) confirms network reachability, no authentication prerequisite and no confidentiality or integrity impact, with only a low availability effect confined to the vulnerable component. The CPE record cpe:2.3:a:openclaw:openclaw:*:*:*:*:*:*:*:* and the EUVD affected range (2026.3.25 < 2026.8.1) both point to the OpenClaw application itself, not to Synology Chat, which is only the peer protocol involved.
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Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Primary rating from Vendor (VulnCheck) · only source for this CVE.
CVSS VectorVendor: VulnCheck
Lifecycle Timeline
1DescriptionCVE.org
OpenClaw versions >= 2026.3.25 and < 2026.8.1 apply invalid-token rate limiting for Synology Chat webhooks before authentication and key the limit on the raw proxy socket address. In deployments where OpenClaw sits behind a trusted reverse proxy or tunnel and multiple external clients share a single socket address, an unauthenticated sender can exhaust the shared invalid-token budget, causing subsequent legitimate Synology Chat webhook callbacks to be rejected until the rate-limit window expires. The attacker cannot obtain a valid token or read message data; the impact is temporary loss of channel availability. Fixed in 2026.8.1.
Threat Intelligence Overview
NVD
CVE.org
EPSS
Vulnrichment
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
Auth bypass in OpenClaw voice-call extension before 2026.2.1. EPSS 0.68%. PoC and patch available.
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OpenClaw versions prior to 2026.2.22 contain a resource exhaustion vulnerability where the application fails to consiste
Exploit-DB