Description
The set_fat function in fat.c in dosfstools before 4.0 might allow attackers to corrupt a FAT12 filesystem or cause a denial of service (invalid memory read and crash) by writing an odd number of clusters to the third to last entry on a FAT12 filesystem, which triggers an "off-by-two error."
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 | dosfstools | 4.0-1 | — |
| Debian 13 | dosfstools | 4.0-1 | — |
| Debian 12 | dosfstools | 4.0-1 | — |
| Debian 8 | dosfstools | 3.0.27-1+deb8u1 | DLA-2224-1 |
| Debian 7 | dosfstools | 3.0.13-1+deb7u1 | DLA-474-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | dosfstools | 3.0.28-2ubuntu0.1 | USN-2986-1 |
| Ubuntu 14.04 LTS | dosfstools | 3.0.26-1ubuntu0.1 | USN-2986-1 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP1 | dosfstools | 3.0.26-6.5 | SUSE-SU-2016:2145-1 |
| SLES 11 SP4 | dosfstools | 3.0.26-3.1 | SUSE-SU-2016:2146-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP1 | dosfstools | 3.0.26-6.5 | SUSE-SU-2016:2145-1 |
| SLES for SAP 11 SP4 | dosfstools | 3.0.26-3.1 | SUSE-SU-2016:2146-1 |
Advisories 5
- DLA-474-1 dosfstools - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2224-1 dosfstools - security update Debian Security (DSA / DLA) · Mar 9, 2026
- USN-2986-1 dosfstools vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
- SUSE-SU-2016:2145-1 Security update for dosfstools SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:2146-1 Security update for dosfstools SUSE / openSUSE Security Updates · Feb 4, 2026
References
- openSUSE-SU-2016:1461 vendor-advisory
- https://github.com/dosfstools/dosfstools/releases/tag/v4.0
- https://github.com/dosfstools/dosfstools/issues/12
- https://blog.fuzzing-project.org/44-dosfstools-fsck.vfat-Several-invalid-memory-accesses.html
- USN-2986-1 vendor-advisory
- https://github.com/dosfstools/dosfstools/commit/07908124838afcc99c577d1d3e84cef2dbd39cb7
- openSUSE-SU-2016:2233 vendor-advisory
- 90311 vdb-entry
- [debian-lts-announce] 20200530 [SECURITY] [DLA 2224-1] dosfstools security update mailing-list