Description
An unauthenticated remote attacker can exhaust
server memory via the FindServers Discovery Service in open62541. The
serverUris field of FindServersRequest is not validated for length or array
size. An attacker can declare an arbitrarily large string (up to ~3.9 GB)
delivered across intermediate chunks without ever sending the final chunk. The
server buffers all chunks in RAM indefinitely until the SecureChannel times
out. The attack is pre-session and bypasses all encryption configuration. The issue affects open62541: from 1.4.0 through 1.4.16, from 1.5.0 through 1.5.4, master.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| open62541 project / o6 Automation | open62541 | 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 | — |
| Ubuntu 25.10 | open62541 | No fix yet | — |