Description
An unsigned integer underflow in the PubSub signature verification path
in open62541 may allow a remote attacker to cause a denial of service
via a crafted UDP packet.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| o6 Automation | open62541 | 1.3.0 – ≤ 1.3.17, 1.4.0 – ≤ 1.4.16, 1.5.0 – ≤ 1.5.4, master | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | open62541 | No fix yet | — |
| Debian 13 | open62541 | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | open62541 | No fix yet | — |
| Ubuntu 26.04 LTS | open62541 | No fix yet | — |
Advisories 1
- ICSA-26-211-08 o6 Automation open62541 CISA ICS & IT advisories · Jul 30, 2026
References
- https://www.o6-automation.com/contact
- https://github.com/open62541/open62541/pull/8235/commits/b666d35769ce63998442e4d0810a3fb10b50179f
- https://github.com/open62541/open62541/pull/8236/commits/06b99fef667c8ec5bdf0605b4f00c84fcc1d3a60
- https://github.com/open62541/open62541/pull/8237/commits/1b71d9c5d9c4d02d4729b8903a52e9f530bf804e
- https://github.com/open62541/open62541/pull/8238/commits/afab4107bfd161da9ce8bb30ed77f3968c9c97df
- https://www.cisa.gov/news-events/ics-advisories/icsa-26-211-08
- https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-211-08.json