Security readout for executives and security teams
Plain-English summary
CVE-2021-23772 is an arbitrary file write issue in the Go Iris web framework upload helper. If an application uses the affected UploadFormFiles path for user uploads, a low-privileged attacker may be able to write files outside the intended upload folder. Business impact depends on where the app runs and what the process can write.
Executive priority
Treat this as a high-priority dependency and upload-surface review, especially for internet-facing applications with authenticated upload features. It is not confirmed actively exploited in the provided evidence, but arbitrary file write can become severe in permissive deployments.
Technical view
The issue is unsafe handling of uploaded filenames in github.com/kataras/iris and github.com/kataras/iris/v12 UploadFormFiles. The CVSS vector is 7.5 high: network reachable, high complexity, low privileges, no user interaction, with high confidentiality, integrity, and availability impact. The source bundle references an upstream commit but does not name a fixed release.
Likely exposure
Exposure is likely limited to Go applications using Iris or Iris v12 and specifically accepting untrusted file uploads through UploadFormFiles. Applications that include Iris but do not use this upload helper are not shown exposed by the provided sources.
Exploitation context
The source bundle does not show CISA KEV listing or active exploitation. Exploitation requires low privileges and high complexity according to CVSS. Successful abuse could write outside the designated upload directory, with impact shaped by filesystem permissions and deployment layout.
Researcher notes
The evidence identifies affected packages and the vulnerable API pattern, but not a fixed version. Validate exposure by combining dependency inventory with code-level UploadFormFiles usage. Avoid assuming every Iris application is exploitable without the upload code path and filesystem context.
Mitigation direction
- Check Snyk and Iris upstream guidance for the fixed release or confirmed remediation path.
- Update Iris only to a version confirmed to contain the referenced upstream fix.
- Restrict or disable affected upload endpoints until remediation is verified.
- Reduce application filesystem write permissions around upload paths and sensitive directories.
- Add server-side filename normalization and path containment checks where uploads are handled.
Validation and detection
- Inventory go.mod and go.sum for github.com/kataras/iris and github.com/kataras/iris/v12.
- Search application code for UploadFormFiles usage.
- Map each UploadFormFiles caller to public or authenticated upload routes.
- Confirm whether deployed versions include upstream commit e213dba0d32ff66653e0ef124bc5088817264b08.
- Review runtime permissions for directories writable by the web application process.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
File access behavior lookup
The CVE wording references file access or upload behavior, so file telemetry and web shell review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-23772 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H1.65.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://snyk.io/vuln/SNYK-GOLANG-GITHUBCOMKATARASIRIS-2325169CVE reference · x_refsource_MISC
- https://snyk.io/vuln/SNYK-GOLANG-GITHUBCOMKATARASIRISV12-2325170CVE reference · x_refsource_MISC
- https://github.com/kataras/iris/commit/e213dba0d32ff66653e0ef124bc5088817264b08CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.