Description
Beginning in v1.4.1 and prior to v1.4.9, due to an incomplete fix for CVE-2021-24031, the Zstandard command-line utility created output files with default permissions and restricted those permissions immediately afterwards. Output files could therefore momentarily be readable or writable to unintended parties.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Zstandard | 1.4.1 – < unspecified | unspecified |
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 | libzstd | 1.4.8+dfsg-2 | — |
| Debian 13 | libzstd | 1.4.8+dfsg-2 | — |
| Debian 12 | libzstd | 1.4.8+dfsg-2 | — |
| Debian 10 | libzstd | 1.3.8+dfsg-3+deb10u2 | DSA-4859-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | libzstd | 1.4.4+dfsg-3ubuntu0.1 | USN-4760-1 |
| Ubuntu 18.04 LTS | libzstd | 1.3.3+dfsg-2ubuntu1.2 | USN-4760-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 16.04 LTS | libzstd | 1.3.1+dfsg-1~ubuntu0.16.04.1+esm3 | USN-5720-1 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP2 | zstd | 1.4.4-1.6.1 | SUSE-SU-2021:0948-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLE Micro 5.0 | zstd | 1.4.4-1.6.1 | SUSE-SU-2021:0948-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 15.2 | zstd | 1.4.4-lp152.2.3.1 | openSUSE-SU-2021:0481-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | zstd | 1.4.9-r0 | — |
| Alpine v3.23 | zstd | 1.4.9-r0 | — |
| Alpine v3.22 | zstd | 1.4.9-r0 | — |
| Alpine v3.21 | zstd | 1.4.9-r0 | — |
| Alpine v3.20 | zstd | 1.4.9-r0 | — |
Show 9 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | zstd | 1.4.9-r0 | — |
| Alpine v3.18 | zstd | 1.4.9-r0 | — |
| Alpine v3.17 | zstd | 1.4.9-r0 | — |
| Alpine v3.16 | zstd | 1.4.9-r0 | — |
| Alpine v3.15 | zstd | 1.4.9-r0 | — |
| Alpine v3.14 | zstd | 1.4.9-r0 | — |
| Alpine v3.13 | zstd | 1.4.9-r0 | — |
| Alpine v3.12 | zstd | 1.4.9-r0 | — |
| Alpine v3.11 | zstd | 1.4.9-r0 | — |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | ceph | 18.2.2-5 | — |
| Azure Linux 2 (CBL-Mariner) | ceph | 16.2.10-3 | — |
Advisories 5
- USN-5720-1 libzstd vulnerabilities Ubuntu Security Notices (USN) · Jun 25, 2026
- USN-4760-1 libzstd vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DSA-4859-1 libzstd - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2021:0948-1 Security update for zstd SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:0481-1 Security update for zstd SUSE / openSUSE Security Updates · Feb 4, 2026