Description
libmspack through 0.11alpha contains an uninitialized memory disclosure vulnerability in the MS-ZIP decompressor that allows attackers to leak heap data via unchecked back-reference distances. Attackers can supply a crafted MS-ZIP CAB file whose first block begins with a back-reference, causing cabd->extract() to write up to 32 KiB of stale heap memory into extracted output.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| kyz | libmspack | ≤ 0.11alpha | — |
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 | libmspack | No fix yet | — |
| Debian 13 | libmspack | No fix yet | — |
| Debian 12 | libmspack | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | libmspack | No fix yet | — |
| Ubuntu 26.04 LTS | libmspack | No fix yet | — |
| Ubuntu 24.04 LTS | libmspack | No fix yet | — |
| Ubuntu 22.04 LTS | libmspack | No fix yet | — |
| Ubuntu 20.04 LTS | libmspack | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | libmspack | No fix yet | — |
| Ubuntu 16.04 LTS | libmspack | No fix yet | — |
| Ubuntu Pro 14.04 LTS | clamav +1 | No fix yet | — |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | clamav +1 | No fix yet | — |
References
- https://github.com/kyz/libmspack/issues/60 issue-tracking
- https://github.com/kyz/libmspack/blob/v0.11alpha/libmspack/mspack/mszipd.c#L264-L276 technical-description
- https://hackmd.io/@haindpwn/libmspack-mszip-uninit-window-info-leak third-party-advisory
- https://github.com/kyz/libmspack product
- VulnCheck Advisory: libmspack through 0.11alpha Uninitialized Memory Disclosure via MS-ZIP Decompressor Window third-party-advisory