Description
The Eclipse Mosquitto broker up to version 1.4.15 does not reject strings that are not valid UTF-8. A malicious client could cause other clients that do reject invalid UTF-8 strings to disconnect themselves from the broker by sending a topic string which is not valid UTF-8, and so cause a denial of service for the clients.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| The Eclipse Foundation | Eclipse Mosquitto | unspecified – ≤ 1.4.15 | — |
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 | mosquitto | 1.5.4-1 | — |
| Debian 13 | mosquitto | 1.5.4-1 | — |
| Debian 12 | mosquitto | 1.5.4-1 | — |
| Debian 9 | mosquitto | 1.4.10-3+deb9u2 | DSA-4325-1 |
| Debian 8 | mosquitto | 1.3.4-2+deb8u3 | DLA-1525-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | mosquitto | 1.4.15-2ubuntu0.18.04.3 | USN-4023-1 |
| Ubuntu 16.04 LTS | mosquitto | 1.4.8-1ubuntu0.16.04.7 | USN-4023-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 14.04 LTS | mosquitto | No fix yet | — |
Advisories 4
- USN-4023-1 mosquitto vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- DSA-4325-1 mosquitto - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-1525-1 mosquitto - security update Debian Security (DSA / DLA) · Mar 9, 2026
- WID-SEC-2023-1737 Juniper Patchday Juli 2023 BSI CERT-Bund (WID) · Jul 12, 2023