There is a possible tty hijacking in shadow 4.x before 4.1.5 and sudo 1.x before 1.7.4 via "su - user -c program".
There is a possible tty hijacking in shadow 4.x before 4.1.5 and sudo 1.x before 1.7.4 via "su - user -c program". The user session can be escaped to the parent session by using the TIOCSTI ioctl to push characters into the input buffer to be read by the next process.
- Published
- Nov 4, 2019
- Updated
- Jun 16, 2026
- EPSS
- 0.6% · 48th percentile
- CWE
- CWE-20
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Report tools
Action score
31
Monitor
Low priority for now.
- CVSS
- 31 / 40 · 7.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.6%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| debian | shadow | cpe:2.3:a:debian:shadow |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
| sudo project | sudo | cpe:2.3:a:sudo_project:sudo |
| redhat | enterprise linux | cpe:2.3:o:redhat:enterprise_linux |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- debian debian linux10.0
- debian debian linux8.0
- debian debian linux9.0
- debian shadow4.0.0 and later · up to 4.1.5 inclusive
- redhat enterprise linux4
- redhat enterprise linux5
- redhat enterprise linux6.0
- sudo project sudo1.3.0 and later · up to 1.7.4 inclusive
Versions reported by the vendor
Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.
Red Hat shadow
- 4.x before 4.1.5affected
Red Hat sudo
- 1.x before 1.7.4affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | shadow | before 1:4.1.5-1 | 1:4.1.5-1 |
| Debian:12 | sudo | before 1.7.4p4 | 1.7.4p4 |
Same product
debian: all recordsOther highest-scoring records for the same primary product.
- CVE-2017-20002The Debian shadow package before 1:4.5-1 for Shadow incorrectly lists pts/0 and pts/1 as physical terminals in /etc/securetty.31Monitor
- CVE-2008-5394/bin/login in shadow 4.0.18.1 in Debian GNU/Linux, and probably other Linux distributions, allows local users in the utmp group to overwrite28Monitor
- CVE-2011-0721Multiple CRLF injection vulnerabilities in (1) chfn and (2) chsh in shadow 1:4.1.4 allow local users to add new users or groups to /etc/pass26Monitor
- CVE-2013-4235shadow: TOCTOU (time-of-check time-of-use) race condition when copying and removing directory trees18Monitor
- CVE-2004-1001Unknown vulnerability in the passwd_check function in Shadow 4.0.4.1, and possibly other versions before 4.0.5, allows local users to conduc18Monitor
- CVE-2006-1174useradd in shadow-utils before 4.0.3, and possibly other versions before 4.0.8, does not provide a required argument to the open function wh14Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| debian:shadow | 1:4.1.5-1 · Debian:12 | Package registry (OSV) |
| debian:sudo | 1.7.4p4 · Debian:12 | Package 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.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
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
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-20 · Improper Input ValidationCVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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.
Attack patterns (CAPEC)
- Buffer Overflow via Environment VariablesCAPEC-10likelihood: High · High
- Server Side Include (SSI) InjectionCAPEC-101likelihood: High · High
- Cross Zone ScriptingCAPEC-104likelihood: Medium · High
- Command Line Execution through SQL InjectionCAPEC-108likelihood: Low · Very High
- Object Relational Mapping InjectionCAPEC-109likelihood: Low · High
- SQL Injection through SOAP Parameter TamperingCAPEC-110likelihood: High · Very High
- Double EncodingCAPEC-120likelihood: Low · Medium
- Subverting Environment Variable ValuesCAPEC-13likelihood: High · Very High
ATT&CK techniques
- Obfuscated Files or InformationT1027
- Masquerading: Invalid Code SignatureT1036.001
- Steal Web Session CookieT1539
- Subvert Trust Controls: Code SigningT1553.002
- Impair Defenses:Impair Command History LoggingT1562.003
- Hijack Execution Flow:Dynamic Linker HijackingT1574.006
- Hijack Execution Flow:Path Interception by PATH Environment VariableT1574.007
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- www.openwall.com/lists/oss-security/2012/11/06/8
- www.openwall.com/lists/oss-security/2013/05/20/3
- www.openwall.com/lists/oss-security/2013/11/28/10
- www.openwall.com/lists/oss-security/2013/11/29/5
- www.openwall.com/lists/oss-security/2014/10/20/9
- www.openwall.com/lists/oss-security/2014/10/21/1
- www.openwall.com/lists/oss-security/2014/12/15/5
- access.redhat.com/security/cve/cve-2005-4890
- bugzilla.redhat.com/show_bug.cgi?id=CVE-2005-4890
- security-tracker.debian.org/tracker/CVE-2005-4890
Vendor advisories and official records. Exploit/PoC links are deliberately left out.