Improper Restriction of Excessive Authentication Attempts in OPTO 22 SNAP PAC S1 Built-in Web Server

published 2023-08-24 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-45261

cvss: 8.6; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.7%; EPSS 0.7% chance of exploitation in 30 days, percentile 52%
public exploits: 0; none known

There is no limit on the number of login attempts in the web server for the SNAP PAC S1 Firmware version R10.3b. This could allow for a brute-force attack on the built-in web server login.

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-23-236-02 updated 2023-08-24 cvss 7.5

OPTO 22 SNAP PAC S1

OPTO 22 SNAP PAC S1 Firmware R10.3b
affected: mitigation “OPTO 22 recommends users follow the direction Dragos and CISA provided for this vulnerability.”

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: partial
Assessed: 2 y ago (2024-10-02)

Exploit prediction

0.67% chance of exploitation in the next 30 days, higher than 52% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	8.6	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
NVD	3.1	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

OPTO 22 SNAP PAC S1
opto22 snap_pac_s1

Classification

Weakness

CWE-307 Improper Restriction of Excessive Authentication Attempts

References

cisa.gov /news-events/ics-advisories/icsa-23-236-02
third-party-advisory, us-government-resource

Sources

CVE List CVE-2023-40706
NVD CVE-2023-40706

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary