Description
PackLinuxElf64::unpack in p_lx_elf.cpp in UPX 3.95 allows remote attackers to cause a denial of service (double free), limit the ability of a malware scanner to operate on the entire original data, or possibly have unspecified other impact via a crafted file.
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 | 1.03+repack-5 | — |
| Debian 13 | upx-ucl | 1.03+repack-5 | — |
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 SP1 | ucl | 1.03-bp151.4.3.1 | openSUSE-SU-2020:0179-1 |
| SUSE Package Hub 15 SP1 | upx | 3.96-bp151.4.3.1 | openSUSE-SU-2020:0180-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | ucl | 1.03-4.9 | openSUSE-SU-2024:11477-1 |
| openSUSE Tumbleweed | upx | 3.96-3.2 | openSUSE-SU-2024:11486-1 |
| openSUSE Leap 15.1 | ucl | 1.03-lp151.3.3.1 | openSUSE-SU-2020:0162-1 |
| openSUSE Leap 15.1 | upx | 3.96-lp151.3.3.1 | openSUSE-SU-2020:0163-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | upx | 3.96-r0 | — |
| Alpine v3.23 | upx | 3.96-r0 | — |
| Alpine v3.22 | upx | 3.96-r0 | — |
| Alpine v3.21 | upx | 3.96-r0 | — |
| Alpine v3.20 | upx | 3.96-r0 | — |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | upx | 3.96-r0 | — |
| Alpine v3.18 | upx | 3.96-r0 | — |
| Alpine v3.17 | upx | 3.96-r0 | — |
| Alpine v3.16 | upx | 3.96-r0 | — |
| Alpine v3.15 | upx | 3.96-r0 | — |
| Alpine v3.14 | upx | 3.96-r0 | — |
| Alpine v3.13 | upx | 3.96-r0 | — |
| Alpine v3.12 | upx | 3.96-r0 | — |
Advisories 6
- openSUSE-SU-2024:11477-1 libucl1-1.03-4.9 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2020:0179-1 Security update for ucl SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2020:0163-1 Security update for upx SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2020:0180-1 Security update for upx SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2020:0162-1 Security update for ucl 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/206
- https://github.com/upx/upx/blob/devel/NEWS
- https://github.com/upx/upx/issues/207
- FEDORA-2020-20cf0743f5 vendor-advisory
- openSUSE-SU-2020:0162 vendor-advisory
- openSUSE-SU-2020:0163 vendor-advisory
- openSUSE-SU-2020:0180 vendor-advisory
- openSUSE-SU-2020:0179 vendor-advisory
- FEDORA-2020-67590fbf08 vendor-advisory