Description
When Eclipse Mosquitto version 1.0 to 1.5.5 (inclusive) is configured to use an ACL file, and that ACL file is empty, or contains only comments or blank lines, then Mosquitto will treat this as though no ACL file has been defined and use a default allow policy. The new behaviour is to have an empty ACL file mean that all access is denied, which is not a useful configuration but is not unexpected.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| The Eclipse Foundation | Eclipse Mosquitto | 1.0 – < unspecified, unspecified – ≤ 1.5.5 | unspecified |
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 | 1.5.6-1 | — |
| Debian 13 | mosquitto | 1.5.6-1 | — |
| Debian 12 | mosquitto | 1.5.6-1 | — |
| Debian 9 | mosquitto | 1.4.10-3+deb9u3 | DSA-4388-1 |
| Debian 8 | mosquitto | 1.3.4-2+deb8u4 | DLA-1972-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | mosquitto | 1.4.15-2ubuntu0.18.04.1 | — |
| Ubuntu 16.04 LTS | mosquitto | 1.4.8-1ubuntu0.16.04.5 | — |
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 | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SUSE Package Hub 15 | mosquitto | 1.4.15-bp150.3.3.1 | openSUSE-SU-2019:0237-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | mosquitto | 1.5.6-r0 | — |
| Alpine v3.23 | mosquitto | 1.5.6-r0 | — |
| Alpine v3.22 | mosquitto | 1.5.6-r0 | — |
| Alpine v3.21 | mosquitto | 1.5.6-r0 | — |
| Alpine v3.20 | mosquitto | 1.5.6-r0 | — |
Show 13 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | mosquitto | 1.5.6-r0 | — |
| Alpine v3.18 | mosquitto | 1.5.6-r0 | — |
| Alpine v3.17 | mosquitto | 1.5.6-r0 | — |
| Alpine v3.16 | mosquitto | 1.5.6-r0 | — |
| Alpine v3.15 | mosquitto | 1.5.6-r0 | — |
| Alpine v3.14 | mosquitto | 1.5.6-r0 | — |
| Alpine v3.13 | mosquitto | 1.5.6-r0 | — |
| Alpine v3.12 | mosquitto | 1.5.6-r0 | — |
| Alpine v3.11 | mosquitto | 1.5.6-r0 | — |
| Alpine v3.10 | mosquitto | 1.5.6-r0 | — |
| Alpine v3.9 | mosquitto | 1.5.6-r0 | — |
| Alpine v3.8 | mosquitto | 1.4.15-r4 | — |
| Alpine v3.7 | mosquitto | 1.4.15-r1 | — |
Advisories 3
- DSA-4388-1 mosquitto - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-1972-1 mosquitto - security update Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2019:0237-1 Security update for mosquitto SUSE / openSUSE Security Updates · Feb 4, 2026