CVE-2021-21364

lowpriority · track · 22EPSS 0.003 · 21 %ileDEEUUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
0.28% (21st) EPSS
CVSS 2.1 · low
Is it mine?
5 products
Check your exposure
Who says so?
5 sources
cnnvd · enisa_euvd · cert_bund · nvd

EPSS · scored 2026-10-27

swagger-codegen is an open-source project which contains a template-driven engine to generate documentation, API clients and server stubs in different languages by parsing your OpenAPI / Swagger definition. In swagger-codegen before version 2.4.19, on Unix-Like systems, the system temporary directory is shared between all local users. When files/directories are created, the default `umask` settings for the process are respected. As a result, by default, most processes/apis will create files/directories with the permissions `-rw-r--r--` and `drwxr-xr-x` respectively, unless an API that explicitly sets safe file permissions is used. Because this vulnerability impacts generated code, the generated code will remain vulnerable until fixed manually! This vulnerability is fixed in version 2.4.19. Note this is a distinct vulnerability from CVE-2021-21363.

01

cvss

Technical severity, 0–10. One row per scoring source.

6.2
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–medium · 2.1–6.2

v2.02.1lowAV:L/AC:L/Au:N/C:P/I:N/A:Nprimary · NVD / NIST USexploitability 3.9 · impact 2.9
v3.15.5mediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:Nprimary · NVD / NIST USexploitability 1.8 · impact 3.6
v3.15.3mediumCVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:H/I:N/A:Nsecondary · ENISA EU
v3.15.3mediumCVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:H/I:N/A:Nsecondary · security-advisories@github.comexploitability 0.8 · impact 4
v3.16.2mediumCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:Nsecondary · OSV
v3.15.1mediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:Usecondary · CVSS-BT (t0sche)
02

weaknesses

The CWE weakness classes this flaw belongs to.

03

affected products (5)

Products and version ranges known to be affected.

04

advisories (2)

Vendor and ecosystem advisories describing this.

  • WID-SEC-W-2026-0180Dell Data Protection Advisor: Mehrere SchwachstellenDeutsch2026-01-20csaf · cert_bundDE

    Ein Angreifer kann mehrere Schwachstellen in Dell Data Protection Advisor ausnutzen, um beliebigen Code auszuführen, einen Denial-of-Service-Zustand zu erzeugen, Sicherheitsmaßnahmen zu umgehen und nicht näher spezifizierte Angriffe zu starten.

  • GHSA-hpv8-9rq5-hq7wGenerated Code Contains Local Information Disclosure Vulnerability2021-03-11ghsa · osvUS

    ### Impact **This vulnerability impacts generated code.** If this code was generated as a one-off occasion, not as a part of an automated CI/CD process, this code will remain vulnerable until fixed manually! On Unix-Like systems, the system temporary directory is shared between all local users. When files/directories are created, the default `umask` settings for the process are respected. As a result, by default, most processes/apis will create files/directories with the permissions `-rw-r--r--` and `drwxr-xr-x` respectively, unless an API that explicitly sets safe file permissions is used. #### Java Code The method `File.createTempFile` from the JDK is vulnerable to this local information disclosure vulnerability. - https://github.com/swagger-api/swagger-codegen/blob/068b1ebcb7b04a48ad38f1cadd24bb3810c9f1ab/modules/swagger-codegen/src/main/resources/kotlin-client/infrastructure/ApiClient.kt.mustache#L209 - https://github.com/swagger-api/swagger-codegen/blob/068b1ebcb7b04a48ad38f1cadd24bb3810c9f1ab/modules/swagger-codegen/src/main/resources/finch/api.mustache#L84 - https://github.com/swagger-api/swagger-codegen/blob/068b1ebcb7b04a48ad38f1cadd24bb3810c9f1ab/modules/swagger-codegen/src/main/resources/Java/libraries/okhttp-gson/ApiClient.mustache#L831-L834 - https://github.com/swagger-api/swagger-codegen/blob/068b1ebcb7b04a48ad38f1cadd24bb3810c9f1ab/modules/swagger-codegen/src/main/resources/Java/libraries/jersey2/ApiClient.mustache#L630-L633 ### Patches Fix has been applied to the master branch with: * https://github.com/swagger-api/swagger-codegen/commit/35adbd552d5f99b3ff1e0e59da228becc85190f2 included in release: 2.4.19 ### Workarounds Users can remediate the vulnerability in non patched version by manually (or programmatically e.g. in CI) updating the generated source code to use `java.nio.files.Files` temporary file creation instead of `java.io.File`, e.g. by changing ```java if (tempFolderPath == null) return File.createTempFile(prefix, suffix); else return File.createTempFile(prefix, suffix, new File(tempFolderPath)); ``` to ```java if (tempFolderPath == null) return Files.createTempFile(prefix, suffix).toFile(); else return Files.createTempFile(Paths.get(tempFolderPath), prefix, suffix).toFile(); ``` or generally changing: ```java File.createTempFile(prefix, suffix); ``` to ```java Files.createTempFile(prefix, suffix).toFile(); ``` ### References * [CWE-378: Creation of Temporary File With Insecure Permissions](https://cwe.mitre.org/data/definitions/378.html) * [CWE-200: Exposure of Sensitive Information to an Unauthorized Actor](https://cwe.mitre.org/data/definitions/200.html) * [CWE-732: Incorrect Permission Assignment for Critical Resource](https://cwe.mitre.org/data/definitions/732.html) ### For more information If you have any questions or comments about this advisory: * Email us at [security@swagger.io](mailto:security@swagger.io) #### Original vulnerability report > I'm performing OSS security research under the GitHub Security Lab Bug Bounty program. > I've been using a custom CodeQL query to find local temporary directory vulnerabilities in OSS with three custom CodeQL queries. > > - https://github.com/github/codeql/pull/4388/files#diff-71d36c0f2bd0b08e32866f873f1c906cdc17277e0ad327c0c6cd2c882f30de4f > - https://github.com/github/codeql/pull/4388/files#diff-1893a18a8bf43c011d61a7889d0139b998a5a78701a30fe7722eddd4c506aaac > - https://github.com/github/codeql/pull/4473 > > The code generated by the Swagger Generator contains a local information disclosure vulnerability. The system temporary directory, on unix-like systems is shared between multiple users. Information written to this directory, or directories created under this directory that do not correctly set the posix standard permissions can have these directories read/modified by other users. > > --- > > This code exists in the code generator, in the generated code. > > In this case, I believe this is only a local information disclosure. IE. another user can read the information, not replace it. > > In particular, the method `File.createTempFile` from the JDK is vulnerable to this local information disclosure vulnerability. > > This is because `File.createTempFile` creates a file inside of the system temporary directory with the permissions: `-rw-r--r--`. Thus the contents of this file are viewable by all other users locally on the system. > > - https://github.com/swagger-api/swagger-codegen/blob/068b1ebcb7b04a48ad38f1cadd24bb3810c9f1ab/modules/swagger-codegen/src/main/resources/kotlin-client/infrastructure/ApiClient.kt.mustache#L209 > - https://github.com/swagger-api/swagger-codegen/blob/068b1ebcb7b04a48ad38f1cadd24bb3810c9f1ab/modules/swagger-codegen/src/main/resources/finch/api.mustache#L84 > - https://github.com/swagger-api/swagger-codegen/blob/068b1ebcb7b04a48ad38f1cadd24bb3810c9f1ab/modules/swagger-codegen/src/main/resources/Java/libraries/okhttp-gson/ApiClient.mustache#L831-L834 > - https://github.com/swagger-api/swagger-codegen/blob/068b1ebcb7b04a48ad38f1cadd24bb3810c9f1ab/modules/swagger-codegen/src/main/resources/Java/libraries/jersey2/ApiClient.mustache#L630-L633 > > The fix here is to switch to the `Files` API, instead of `File` as that appropriately sets the file permissions. >

05

also known as (3)

Other names and identifiers for this entity.

06

sources

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published 2021-03-11modified 2026-06-17
08

references (7)

External citations — patches, advisories, analysis.

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