Description
A heap buffer overflow read was discovered in upx 4.0.0, because the check in p_lx_elf.cpp is not perfect.
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 | upx-ucl | 4.2.2-1 | — |
| Debian 13 | upx-ucl | 4.2.2-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | upx-ucl | No fix yet | — |
| Ubuntu 26.04 LTS | upx-ucl | No fix yet | — |
| Ubuntu 25.10 | upx-ucl | No fix yet | — |
| Ubuntu 24.04 LTS | upx-ucl | No fix yet | — |
| Ubuntu 22.04 LTS | upx-ucl | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | upx-ucl | No fix yet | — |
| Ubuntu 18.04 LTS | upx-ucl | No fix yet | — |
| Ubuntu 16.04 LTS | upx-ucl | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SUSE Package Hub 15 SP3 | upx | 3.96-bp153.2.3.1 | openSUSE-SU-2021:0813-1 |
| SUSE Package Hub 15 SP2 | upx | 3.96-bp152.2.3.1 | openSUSE-SU-2021:0826-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | upx | 3.96-3.2 | openSUSE-SU-2024:11486-1 |
| openSUSE Leap 15.3 | upx | 3.96-bp153.2.3.1 | openSUSE-SU-2021:0813-1 |
| openSUSE Leap 15.2 | upx | 3.96-bp153.2.3.1 | openSUSE-SU-2021:0813-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | upx | 4.0.0-r0 | — |
| Alpine v3.23 | upx | 4.0.0-r0 | — |
| Alpine v3.22 | upx | 4.0.0-r0 | — |
| Alpine v3.21 | upx | 4.0.0-r0 | — |
| Alpine v3.20 | upx | 4.0.0-r0 | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | upx | 4.0.0-r0 | — |
| Alpine v3.18 | upx | 4.0.0-r0 | — |
| Alpine v3.17 | upx | 4.0.0-r0 | — |
Advisories 3
- openSUSE-SU-2021:0826-1 Security update for upx SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:0813-1 Security update for upx SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:11486-1 upx-3.96-3.2 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
References
- https://github.com/upx/upx/issues/388
- FEDORA-2021-737766a313 vendor-advisory
- FEDORA-2021-ceb9db8de0 vendor-advisory
- https://cwe.mitre.org/data/definitions/126.html