Common Weakness Enumeration

CWE-560

Weakness Allowed

Use of umask() with chmod-style Argument

Abstraction: Variant · Status: Draft

The product calls umask() with an incorrect argument that is specified as if it is an argument to chmod().

Mapping guidance

This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

Relationships and members
ChildOf: CWE-687 · View CWE-1000
Modes of introduction
Implementation
Detection methods

Automated Static Analysis

If you suspect misuse of umask(), you can use grep to spot call instances of umask().

Notes

Other

Some umask() manual pages begin with the false statement: "umask sets the umask to mask & 0777" Although this behavior would better align with the usage of chmod(), where the user provided argument specifies the bits to enable on the specified file, the behavior of umask() is in fact opposite: umask() sets the umask to ~mask & 0777. The documentation goes on to describe the correct usage of umask(): "The umask is used by open() to set initial file permissions on a newly-created file. Specifically, permissions in the umask are turned off from the mode argument to open(2) (so, for example, the common umask default value of 022 results in new files being created with permissions 0666 & ~022 = 0644 = rw-r--r-- in the usual case where the mode is specified as 0666)."

Content history
Submission: Anonymous Tool Vendor (under NDA) · 2006-07-19 · CWE Draft 3
Modification: Eric Dalci · Cigital · 2008-07-01 · CWE 1.0

updated Potential_Mitigations

Modification: CWE Content Team · MITRE · 2008-09-08 · CWE 1.0

updated Relationships, Other_Notes, Taxonomy_Mappings

Modification: CWE Content Team · MITRE · 2011-06-01 · CWE 1.13

updated Common_Consequences

Modification: CWE Content Team · MITRE · 2012-05-11 · CWE 2.2

updated Relationships

Modification: CWE Content Team · MITRE · 2012-10-30 · CWE 2.3

updated Potential_Mitigations

Modification: CWE Content Team · MITRE · 2014-07-30 · CWE 2.8

updated Relationships

Modification: CWE Content Team · MITRE · 2017-11-08 · CWE 3.0

updated Taxonomy_Mappings

Modification: CWE Content Team · MITRE · 2020-02-24 · CWE 4.0

updated Relationships

Modification: CWE Content Team · MITRE · 2021-07-20 · CWE 4.5

updated Other_Notes

Modification: CWE Content Team · MITRE · 2023-04-27 · CWE 4.11

updated Relationships

Modification: CWE Content Team · MITRE · 2023-06-29 · CWE 4.12

updated Mapping_Notes

Modification: CWE Content Team · MITRE · 2025-12-11 · CWE 4.19

updated Detection_Factors, Potential_Mitigations, Weakness_Ordinalities

0 vulnerabilities reference this CWE, most recent first.

No vulnerabilities reference this CWE.

Mitigation
Implementation

Use umask() with the correct argument.

No CAPEC attack patterns related to this CWE.