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NVD / CVE Program· CNA mitre

CVE-2023-29383: In Shadow 4.13, it is possible to inject control characters into fields provided to the SUID program chfn (change finger).

LowCVSS 3.3 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 13/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.42% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: cbl2 shadow-utils 4.9-13 on CBL Mariner 2.0 4.9-13.

Low priority for now. Upgrade to cbl2 shadow-utils 4.9-13 on CBL Mariner 2.0 4.9-13 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

Published
Apr 14, 2023
Updated
Oct 14, 2026
EPSS
0.4% · 37th percentile

Report tools

JSON

Action score

13

Monitor

Low priority for now.

CVSS
13 / 40 · 3.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
shadow projectshadow

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • shadow project shadow4.13

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Alpine:v3.18shadowbefore 4.13-r34.13-r3
Alpine:v3.19shadowbefore 4.13-r44.13-r4
Debian:11shadowbefore 1:4.8.1-1+deb11u11:4.8.1-1+deb11u1
Debian:12shadowbefore 1:4.13+dfsg1-1+deb12u11:4.13+dfsg1-1+deb12u1
Debian:13shadowbefore 1:4.13+dfsg1-21:4.13+dfsg1-2
openSUSE:Leap Micro 5.3shadowbefore 4.8.1-150400.10.6.14.8.1-150400.10.6.1
openSUSE:Leap Micro 5.4shadowbefore 4.8.1-150400.3.6.14.8.1-150400.3.6.1
openSUSE:Tumbleweedshadowbefore 4.13-6.14.13-6.1
SUSE:Linux Enterprise High Performance Computing 15 SP1-LTSSshadowbefore 4.6-150100.3.8.14.6-150100.3.8.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-ESPOSshadowbefore 4.8.1-150300.4.6.14.8.1-150300.4.6.1
SUSE:Linux Enterprise Micro 5.3shadowbefore 4.8.1-150400.10.6.14.8.1-150400.10.6.1
SUSE:Linux Enterprise Micro 5.4shadowbefore 4.8.1-150400.3.6.14.8.1-150400.3.6.1
SUSE:Linux Enterprise Micro 5.5shadowbefore 4.8.1-150500.3.3.14.8.1-150500.3.3.1
SUSE:Linux Enterprise Server 12 SP5shadowbefore 4.2.1-36.3.14.2.1-36.3.1
SUSE:OpenStack Cloud 9shadowbefore 4.2.1-27.22.14.2.1-27.22.1

Same product

shadow project: all records

Other highest-scoring records for the same primary product.

  • CVE-2017-12424In shadow before 4.5, the newusers tool could be made to manipulate internal data structures in ways unintended by the authors.
    40Plan
  • CVE-2019-19882shadow 4.8, in certain circumstances affecting at least Gentoo, Arch Linux, and Void Linux, allows local users to obtain root access…
    31Monitor
  • CVE-2016-6252Integer overflow in shadow 4.2.1 allows local users to gain privileges via crafted input to newuidmap.
    31Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2018-7169Feb 15, 2018 · An issue was discovered in shadow 4.5.
    21Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
cbl2 shadow-utils 4.9-13 on CBL Mariner 2.04.9-13 · CBL-Mariner ReleasesMicrosoft (MSRC)
alpine:shadow4.13-r3 · Alpine:v3.18Package registry (OSV)
debian:shadow1:4.13+dfsg1-1+deb12u1 · Debian:12Package registry (OSV)
opensuse:shadow4.8.1-150400.10.6.1 · openSUSE:Leap Micro 5.3Package registry (OSV)
suse:shadow4.8.1-150400.10.6.1 · SUSE:Linux Enterprise Micro 5.3Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Not on record for this CVE: EPSS history · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
low · data or configuration can be modified
Availability
none
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-74 · Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

References

Show all references (4 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records