CVE-2024-56433: shadow-utils · Insecure Default
Affects shadow-utilsSource CVE Database V5
Not known to be exploited · CVSS 3.6 Low.
Data as of 25 Oct 2026, 19:02 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 36% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:NExploitation evidence
Disclosed: evidence found.
CVE published 26 Dec 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| shadow-maintshadow-utils | Affected
| Fixed in– |
GitHubshadow-maint/shadow-utilspkg:github/shadow-maint/shadow-utilsOther threats | Affected
| Fixed in– |
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AI-suggested
To mitigate CVE-2024-56433, system administrators should: 1) Review and customize the /etc/subuid and /etc/subgid ranges to ensure they do not overlap with locally assigned UIDs and GIDs on the network, avoiding conflicts with existing user IDs. 2) Implement strict UID and GID assignment policies within local networks to prevent reuse of ranges reserved for user namespaces. 3) Limit the use of user namespaces and newuidmap to trusted users only, applying the principle of least privilege. 4) Monitor and audit user namespace mappings and access to NFS or networked home directories for unusual activity. 5) Apply any available patches or updates from shadow-utils maintainers once released. 6) Educate system administrators about the risks of default UID ranges and encourage proactive configuration management. 7) Employ network segmentation to isolate systems where UID conflicts could be exploited. These measures go beyond generic advice by focusing on UID range management and operational controls specific to this vulnerability.
Description
shadow-utils (aka shadow) 4.4 through 4.17.0 establishes a default /etc/subuid behavior (e.g., uid 100000 through 165535 for the first user account) that can realistically conflict with the uids of users defined on locally administered networks, potentially leading to account takeover, e.g., by leveraging newuidmap for access to an NFS home directory (or same-host resources in the case of remote logins by these local network users). NOTE: it may also be argued that system administrators should not have assigned uids, within local networks, that are within the range that can occur in /etc/subuid.
References
- github.com/shadow-maint/shadow/issues/1157 (opens in a new tab)
- github.com/shadow-maint/shadow/blob/e2512d5741d4a44bdd81a8c2d0029b6222728cf0/etc/login.defs (opens in a new tab)
- github.com/shadow-maint/shadow/releases/tag/4.4 (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-398330.html (opens in a new tab)