Description
Postorius through 1.3.13 does not escape HTML in the message subject when rendering it in the Held messages pop-up, as exploited in the wild in May 2026.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Postorius project | Postorius | ≤ 1.3.13 | — |
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 | postorius | No fix yet | — |
| Debian 13 | postorius | 1.3.13-1+deb13u1 | — |
| Debian 12 | postorius | 1.3.8-3+deb12u1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | postorius | No fix yet | — |
| Ubuntu 26.04 LTS | postorius | 1.3.13-1ubuntu1.1~26.04.1 | USN-8323-1 |
| Ubuntu 25.10 | postorius | 1.3.13-1ubuntu1.1~25.10.1 | USN-8323-1 |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 24.04 LTS | postorius | 1.3.10-1ubuntu0.1~esm1 | USN-8323-1 |
| Ubuntu Pro 22.04 LTS | postorius | 1.3.5-1ubuntu0.1~esm1 | USN-8323-1 |
| Ubuntu Pro 20.04 LTS | postorius | 1.2.4-1ubuntu0.1+esm1 | USN-8323-1 |
| Ubuntu Pro 18.04 LTS | postorius | 1.1.2-3ubuntu0.1+esm1 | USN-8323-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | python-postorius | 1.3.13-8.1 | openSUSE-SU-2026:11539-1 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | postorius | <= 1.3.13 | — | GHSA-r7c9-7pjq-hmm8 |
Advisories 2
- openSUSE-SU-2026:11539-1 postorius-1.3.13-8.1 on GA media SUSE / openSUSE Security Updates · Aug 19, 2026
- USN-8323-1 postorius vulnerability Ubuntu Security Notices (USN) · May 27, 2026