Description
In Shadow 4.13, it is possible to inject control characters into fields provided to the SUID program chfn (change finger). Although it is not possible to exploit this directly (e.g., adding a new user fails because \n is in the block list), it is possible to misrepresent the /etc/passwd file when viewed. Use of \r manipulations and Unicode characters to work around blocking of the : character make it possible to give the impression that a new user has been added. In other words, an adversary may be able to convince a system administrator to take the system offline (an indirect, social-engineered denial of service) by demonstrating that "cat /etc/passwd" shows a rogue user account.
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 | 1:4.13+dfsg1-2 | — |
| Debian 13 | shadow | 1:4.13+dfsg1-2 | — |
| Debian 12 | shadow | 1:4.13+dfsg1-1+deb12u1 | — |
| Debian 11 | shadow | 1:4.8.1-1+deb11u1 | DLA-4130-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 22.04 LTS | shadow | No fix yet | — |
| Ubuntu 20.04 LTS | shadow | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 18.04 LTS | shadow | No fix yet | — |
| Ubuntu Pro 16.04 LTS | shadow | No fix yet | — |
| Ubuntu Pro 14.04 LTS | shadow | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP4 | shadow | 4.8.1-150400.10.6.1 | SUSE-SU-2023:2066-1 |
| SLES 15 SP3 | shadow | 4.8.1-150300.4.6.1 | SUSE-SU-2023:2070-1 |
| SLES 15 SP2 | shadow | 4.6-150100.3.8.1 | SUSE-SU-2023:2068-1 |
| SLES 15 SP1 | shadow | 4.6-150100.3.8.1 | SUSE-SU-2023:2068-1 |
| SLES 12 SP5 | shadow | 4.2.1-36.3.1 | SUSE-SU-2023:2067-1 |
Show 22 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP4 | shadow | 4.2.1-27.22.1 | SUSE-SU-2023:2069-1 |
| SLES 12 SP2 | shadow | 4.2.1-27.22.1 | SUSE-SU-2023:2069-1 |
| SLES for SAP 15 SP3 | shadow | 4.8.1-150300.4.6.1 | SUSE-SU-2023:2070-1 |
| SLES for SAP 15 SP2 | shadow | 4.6-150100.3.8.1 | SUSE-SU-2023:2068-1 |
| SLES for SAP 15 SP1 | shadow | 4.6-150100.3.8.1 | SUSE-SU-2023:2068-1 |
| SLES for SAP 12 SP5 | shadow | 4.2.1-36.3.1 | SUSE-SU-2023:2067-1 |
| SLES for SAP 12 SP4 | shadow | 4.2.1-27.22.1 | SUSE-SU-2023:2069-1 |
| SLE Real Time 15 SP3 | shadow | 4.8.1-150300.4.6.1 | SUSE-SU-2023:2070-1 |
| SLE Micro 5.5 | shadow | 4.8.1-150500.3.3.1 | SUSE-SU-2024:1007-2, SUSE-SU-2024:1007-1 |
| SLE Micro 5.4 | shadow | 4.8.1-150400.3.6.1 | SUSE-SU-2024:0939-1 |
| SLE Micro 5.3 | shadow | 4.8.1-150400.10.6.1 | SUSE-SU-2023:2066-1 |
| SLE Micro 5.2 | shadow | 4.8.1-150300.4.6.1 | SUSE-SU-2023:2070-1 |
| SLE Micro 5.1 | shadow | 4.8.1-150300.4.6.1 | SUSE-SU-2023:2070-1 |
| SLE HPC 15 SP3 | shadow | 4.8.1-150300.4.6.1 | SUSE-SU-2023:2070-1 |
| SLE HPC 15 SP2 | shadow | 4.6-150100.3.8.1 | SUSE-SU-2023:2068-1 |
| SLE HPC 15 SP1 | shadow | 4.6-150100.3.8.1 | SUSE-SU-2023:2068-1 |
| SUSE OpenStack Cloud Crowbar 9 | shadow | 4.2.1-27.22.1 | SUSE-SU-2023:2069-1 |
| SUSE OpenStack Cloud 9 | shadow | 4.2.1-27.22.1 | SUSE-SU-2023:2069-1 |
| SUSE Manager Server 4.2 | shadow | 4.8.1-150300.4.6.1 | SUSE-SU-2023:2070-1 |
| SUSE Manager Proxy 4.2 | shadow | 4.8.1-150300.4.6.1 | SUSE-SU-2023:2070-1 |
| SUSE Enterprise Storage 7.1 | shadow | 4.8.1-150300.4.6.1 | SUSE-SU-2023:2070-1 |
| SUSE Enterprise Storage 7 | shadow | 4.6-150100.3.8.1 | SUSE-SU-2023:2068-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | shadow | 4.13-6.1 | openSUSE-SU-2024:12881-1 |
| openSUSE Leap 15.4 | shadow | 4.8.1-150400.10.6.1 | SUSE-SU-2023:2066-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap Micro 5.4 | shadow | 4.8.1-150400.3.6.1 | SUSE-SU-2024:0939-1 |
| openSUSE Leap Micro 5.3 | shadow | 4.8.1-150400.10.6.1 | SUSE-SU-2023:2066-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | shadow | 4.13-r4 | — |
| Alpine v3.23 | shadow | 4.13-r4 | — |
| Alpine v3.22 | shadow | 4.13-r4 | — |
| Alpine v3.21 | shadow | 4.13-r4 | — |
| Alpine v3.20 | shadow | 4.13-r4 | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | shadow | 4.13-r4 | — |
| Alpine v3.18 | shadow | 4.13-r3 | — |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 2 (CBL-Mariner) | shadow-utils | 4.9-13 | — |
Advisories 16
- SSA-398330 SSA-398330: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP >= V3.1.0 and < V3.1.5 Siemens ProductCERT · Oct 13, 2026
- WID-SEC-2024-0794 Dell ECS: Mehrere Schwachstellen BSI CERT-Bund (WID) · Aug 11, 2026
- DLA-4130-1 shadow - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2024:0939-1 Security update for shadow SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2024:1007-2 Security update for shadow SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2023:2067-1 Security update for shadow SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2024:1007-1 Security update for shadow SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2023:2066-1 Security update for shadow SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2023:2069-1 Security update for shadow SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2023:2070-1 Security update for shadow SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2023:2068-1 Security update for shadow SUSE / openSUSE Security Updates · Feb 4, 2026
- NCSC-2025-0382 Kwetsbaarheden verholpen in Siemens producten NCSC-NL (Netherlands) · Dec 9, 2025
- SSA-202008 SSA-202008: Multiple Vulnerabilities in Ruggedcom Rox Before V2.17.0 Siemens ProductCERT · Dec 9, 2025
- WID-SEC-2023-0978 shadow: Schwachstelle ermöglicht Darstellen falscher Informationen BSI CERT-Bund (WID) · Nov 6, 2025
- ICSA-23-348-10 Siemens SIMATIC S7-1500 CISA ICS & IT advisories · Aug 12, 2025
- openSUSE-SU-2024:12881-1 libsubid-devel-4.13-6.1 on GA media SUSE / openSUSE Security Updates · May 7, 2025
References
- https://github.com/shadow-maint/shadow/pull/687
- https://github.com/shadow-maint/shadow/commit/e5905c4b84d4fb90aefcd96ee618411ebfac663d
- https://www.trustwave.com/en-us/resources/security-resources/security-advisories/?fid=31797
- https://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/cve-2023-29383-abusing-linux-chfn-to-misrepresent-etc-passwd/