CVE-2026-63362: o6 Automation open62541 · Integer Underflow
Affects o6 Automation open62541Source CVE Database V5
Not known to be exploited · CVSS 5.9 Medium.
Data as of 29 Oct 2026, 07:15 UTC
- EPSS
- 1.8% chance of exploitation in 30 days – higher than 78% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 30 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| o6 Automationopen62541 | Affected
| Fixed in– |
GitHubopen62541/open62541pkg:github/open62541/open62541Other threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Until an official fix is available, users should consider mitigating exposure by restricting UDP traffic to trusted sources or disabling the vulnerable PubSub feature if feasible. Monitor vendor channels for updates and apply patches promptly once released.
Description
CVE-2026-63362 is an unsigned integer underflow vulnerability in the PubSub signature verification path of the open62541 library by o6 Automation. This flaw may allow a remote attacker to cause a denial of service by sending a crafted UDP packet. The vulnerability affects versions 1.3.0, 1.4.0, and 1.5.0 of open62541. The severity is rated medium with a CVSS score of 5.9. No official patch or remediation guidance is currently available.
References
- o6-automation.com/contact (opens in a new tab)
- github.com/open62541/open62541/pull/8235/commits/b666d35769ce63998442e4d0810a3fb10b50179f (opens in a new tab)
- github.com/open62541/open62541/pull/8236/commits/06b99fef667c8ec5bdf0605b4f00c84fcc1d3a60 (opens in a new tab)
- github.com/open62541/open62541/pull/8237/commits/1b71d9c5d9c4d02d4729b8903a52e9f530bf804e (opens in a new tab)
- github.com/open62541/open62541/pull/8238/commits/afab4107bfd161da9ce8bb30ed77f3968c9c97df (opens in a new tab)
- cisa.gov/news-events/ics-advisories/icsa-26-211-08 (opens in a new tab)
- github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-211-08.json (opens in a new tab)