EUVD-2026-82861
GHSA-hv3x-fr88-gcjp
Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/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
Pre-auth network-reachable web login with low complexity (PR:N/AC:L); described impact is only an authentication-process crash, so C:N/I:N and A:H.
Primary rating from Vendor (Moxa).
CVSS VectorVendor: Moxa
Lifecycle Timeline
3DescriptionCVE.org
An out-of-bounds write vulnerability exists in some of the Ethernet switches because of improper validation of the username field length during Web login processing. This may allow a remote attacker to submit a specially crafted overly long input, triggering a buffer overflow that can cause the authentication process to crash and result in a Denial of Service (DoS) attack.
AnalysisAI
Pre-authentication denial of service in the Moxa TN-4500B series Ethernet switches: improper validation of the username field length during Web login processing lets a remote, unauthenticated attacker send an overly long username that overflows a buffer and crashes the authentication process. No credentials (PR:N) and no user interaction (UI:N) are required, so any TN-4500B switch whose HTTP/HTTPS management login is reachable from the attacker's network is at risk, and the vendor-supplied CVSS 4.0 vector scores it 8.8 with availability impact rated High. …
Unlock full vulnerability intelligence
- Risk assessment & exploitation conditions
- Attack chain visualization
- Remediation with exact patch versions
- Threat intelligence from 22 sources
- Personal watchlist & email alerts
No credit card · 7-day full trial
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires network reachability to the affected Moxa TN-4500B series switch's Web management (login) interface; the attacker sends a specially crafted, overly long username during Web login processing. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The vendor-supplied CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N, score 8.8) describes a pre-authentication, network-reachable flaw of low attack complexity requiring no privileges or user interaction - all signals that favor easy triggering. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | The supplied intelligence does not identify a vendor-released patched firmware version for CVE-2026-15579, so no exact fix version can be cited; the first action is to consult Moxa advisory MPSA-252620 (https://www.moxa.com/en/support/product-support/security-advisory/mpsa-252620-cve-2026-15579-out-of-bounds-write-vulnerability-in-ethernet-switch) and apply the firmware release it designates for the TN-4500B series, scheduling the upgrade in a maintenance window because switch reboots interrupt OT traffic. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, identify all internet- or broadly reachable Moxa TN-4500B switches and immediately block inbound HTTP/HTTPS management traffic from untrusted networks via firewall or ACL rules; if web management is not essential for operations, disable it entirely. …
Sign in for detailed remediation steps and compensating controls.
Threat intelligence, references, and detailed analysis are available after sign-in.
Same weakness CWE-787 – Out-of-bounds Write
View allSame technique Buffer Overflow
View allShare
External POC / Exploit Code
Leaving vuln.today