Description
LibEtPan through 1.9.4, as used in MailCore 2 through 0.6.3 and other products, has a STARTTLS buffering issue that affects IMAP, SMTP, and POP3. When a server sends a "begin TLS" response, the client reads additional data (e.g., from a meddler-in-the-middle attacker) and evaluates it in a TLS context, aka "response injection."
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 | libetpan | 1.9.4-3 | — |
| Debian 13 | libetpan | 1.9.4-3 | — |
| Debian 12 | libetpan | 1.9.4-3 | — |
| Debian 9 | libetpan | 1.6-3+deb9u1 | DLA-2329-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | libetpan | No fix yet | — |
| Ubuntu 26.04 LTS | libetpan | No fix yet | — |
| Ubuntu 25.10 | libetpan | No fix yet | — |
| Ubuntu 24.04 LTS | libetpan | No fix yet | — |
| Ubuntu 22.04 LTS | libetpan | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | libetpan | 1.6-1ubuntu0.1 | USN-4598-1 |
| Ubuntu Pro 20.04 LTS | libetpan | No fix yet | — |
| Ubuntu Pro 18.04 LTS | libetpan | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SUSE Package Hub 15 SP2 | libetpan | 1.9.4-bp152.4.3.1 | openSUSE-SU-2020:1505-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 15.2 | libetpan | 1.9.4-lp152.3.3.1 | openSUSE-SU-2020:1454-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | libetpan | 1.9.4-r1 | — |
| Alpine v3.23 | libetpan | 1.9.4-r1 | — |
| Alpine v3.22 | libetpan | 1.9.4-r1 | — |
| Alpine v3.21 | libetpan | 1.9.4-r1 | — |
| Alpine v3.20 | libetpan | 1.9.4-r1 | — |
Show 7 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | libetpan | 1.9.4-r1 | — |
| Alpine v3.18 | libetpan | 1.9.4-r1 | — |
| Alpine v3.17 | libetpan | 1.9.4-r1 | — |
| Alpine v3.16 | libetpan | 1.9.4-r1 | — |
| Alpine v3.15 | libetpan | 1.9.4-r1 | — |
| Alpine v3.14 | libetpan | 1.9.4-r1 | — |
| Alpine v3.13 | libetpan | 1.9.4-r1 | — |
Advisories 4
- USN-4598-1 libetpan vulnerability Ubuntu Security Notices (USN) · Apr 27, 2026
- DLA-2329-1 libetpan - security update Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2020:1454-1 Security update for libetpan SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2020:1505-1 Security update for libetpan SUSE / openSUSE Security Updates · Feb 4, 2026
References
- https://github.com/dinhvh/libetpan/issues/386
- GLSA-202007-55 vendor-advisory
- [debian-lts-announce] 20200816 [SECURITY] [DLA 2329-1] libetpan security update mailing-list
- FEDORA-2020-13ae5f7221 vendor-advisory
- FEDORA-2020-44e52ef729 vendor-advisory
- openSUSE-SU-2020:1454 vendor-advisory
- openSUSE-SU-2020:1505 vendor-advisory