Description
A flaw was found in mbsync before v1.3.5 and v1.4.1. Validations of the mailbox names returned by IMAP LIST/LSUB do not occur allowing a malicious or compromised server to use specially crafted mailbox names containing '..' path components to access data outside the designated mailbox on the opposite end of the synchronization channel. The highest threat from this vulnerability is to data confidentiality and integrity.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| — | isync/mbsync | before 1.35, before 1.4.1 | — |
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 | isync | 1.3.0-2.1 | — |
| Debian 13 | isync | 1.3.0-2.1 | — |
| Debian 12 | isync | 1.3.0-2.1 | — |
| Debian 9 | isync | 1.2.1-2+deb9u1 | DLA-3066-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | isync | No fix yet | — |
| Ubuntu 26.04 LTS | isync | No fix yet | — |
| Ubuntu 25.10 | isync | No fix yet | — |
| Ubuntu 24.04 LTS | isync | No fix yet | — |
| Ubuntu 22.04 LTS | isync | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | isync | No fix yet | — |
| Ubuntu 18.04 LTS | isync | No fix yet | — |
| Ubuntu 16.04 LTS | isync | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SUSE Package Hub 15 SP2 | isync | 1.3.5-bp152.4.3.1 | openSUSE-SU-2021:0533-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | isync | 1.4.3-1.2 | openSUSE-SU-2024:10866-1 |
| openSUSE Leap 15.2 | isync | 1.3.5-lp152.4.3.1 | openSUSE-SU-2021:0516-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | isync | 1.4.1-r0 | — |
| Alpine v3.23 | isync | 1.4.1-r0 | — |
| Alpine v3.22 | isync | 1.4.1-r0 | — |
| Alpine v3.21 | isync | 1.4.1-r0 | — |
| Alpine v3.20 | isync | 1.4.1-r0 | — |
Show 7 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | isync | 1.4.1-r0 | — |
| Alpine v3.18 | isync | 1.4.1-r0 | — |
| Alpine v3.17 | isync | 1.4.1-r0 | — |
| Alpine v3.16 | isync | 1.4.1-r0 | — |
| Alpine v3.15 | isync | 1.4.1-r0 | — |
| Alpine v3.14 | isync | 1.4.1-r0 | — |
| Alpine v3.13 | isync | 1.3.5-r0 | — |
Advisories 4
- DLA-3066-1 isync - security update Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2024:10866-1 isync-1.4.3-1.2 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:0516-1 Security update for isync SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:0533-1 Security update for isync SUSE / openSUSE Security Updates · Feb 4, 2026
References
- https://bugzilla.redhat.com/show_bug.cgi?id=1928963
- https://www.openwall.com/lists/oss-security/2021/02/22/1
- FEDORA-2021-954ebabcf7 vendor-advisory
- FEDORA-2021-ef8c2acfce vendor-advisory
- [debian-lts-announce] 20220701 [SECURITY] [DLA 3066-1] isync security update mailing-list
- GLSA-202208-15 vendor-advisory