Description
In shadow before 4.5, the newusers tool could be made to manipulate internal data structures in ways unintended by the authors. Malformed input may lead to crashes (with a buffer overflow or other memory corruption) or other unspecified behaviors. This crosses a privilege boundary in, for example, certain web-hosting environments in which a Control Panel allows an unprivileged user account to create subaccounts.
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 | shadow | 1:4.5-1 | — |
| Debian 13 | shadow | 1:4.5-1 | — |
| Debian 12 | shadow | 1:4.5-1 | — |
| Debian 9 | shadow | 1:4.4-4.1+deb9u1 | DLA-2596-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | shadow | 1:4.5-1ubuntu2.2 | USN-5254-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 16.04 LTS | shadow | 1:4.2-3.1ubuntu5.5+esm1 | USN-5254-1 |
| Ubuntu Pro 14.04 LTS | shadow | 1:4.1.5.1-1ubuntu9.5+esm1 | USN-5254-1 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP3 | shadow | 4.2.1-27.3.3 | SUSE-SU-2017:2947-1 |
| SLES 12 SP2 | shadow | 4.2.1-27.3.3 | SUSE-SU-2017:2947-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP3 | shadow | 4.2.1-27.3.3 | SUSE-SU-2017:2947-1 |
| SLES for SAP 12 SP2 | shadow | 4.2.1-27.3.3 | SUSE-SU-2017:2947-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | shadow | 4.5-r0 | — |
| Alpine v3.23 | shadow | 4.5-r0 | — |
| Alpine v3.22 | shadow | 4.5-r0 | — |
| Alpine v3.21 | shadow | 4.5-r0 | — |
| Alpine v3.20 | shadow | 4.5-r0 | — |
Show 13 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | shadow | 4.5-r0 | — |
| Alpine v3.18 | shadow | 4.5-r0 | — |
| Alpine v3.17 | shadow | 4.5-r0 | — |
| Alpine v3.16 | shadow | 4.5-r0 | — |
| Alpine v3.15 | shadow | 4.5-r0 | — |
| Alpine v3.14 | shadow | 4.5-r0 | — |
| Alpine v3.13 | shadow | 4.5-r0 | — |
| Alpine v3.12 | shadow | 4.5-r0 | — |
| Alpine v3.11 | shadow | 4.5-r0 | — |
| Alpine v3.10 | shadow | 4.5-r0 | — |
| Alpine v3.9 | shadow | 4.5-r0 | — |
| Alpine v3.8 | shadow | 4.5-r0 | — |
| Alpine v3.7 | shadow | 4.5-r0 | — |
Advisories 4
- USN-5254-1 shadow vulnerabilities Ubuntu Security Notices (USN) · Jun 29, 2026
- DLA-2596-1 shadow - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2017:2947-1 Security update for shadow SUSE / openSUSE Security Updates · Feb 4, 2026
- WID-SEC-2025-2505 Shadow: Schwachstelle ermöglicht Privilegieneskalation BSI CERT-Bund (WID) · Nov 6, 2025
References
- https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=756630
- GLSA-201710-16 vendor-advisory
- https://github.com/shadow-maint/shadow/commit/954e3d2e7113e9ac06632aee3c69b8d818cc8952
- https://bugs.launchpad.net/ubuntu/+source/shadow/+bug/1266675
- [debian-lts-announce] 20210317 [SECURITY] [DLA 2596-1] shadow security update mailing-list