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No exploitation reportedFix available

CVE-2021-28966

No exploitation reported by the sources we read.

  • Published2021-07-30
  • Fixed in3.0.1 · 2.7.3
  • WeaknessCWE-22

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

In Ruby through 3.0 on Windows, a remote attacker can submit a crafted path when a Web application handles a parameter with TmpDir.

Timeline

dates in UTC
  1. 2021-07-3014:15CVE publishedNVD

Versions per branch

NVD · OSV
Rubyversion to verify
BranchAffectedFixed in
3.0≥ 3.0.0, < 3.0.13.0.1
2.7< 2.7.32.7.3
tmpdir
BranchAffectedFixed in
0.1< 0.1.20.1.2

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • rubyCleanStartall versions · fixed in 2.7.3-r0and 2 other packages
  • rubyAlpine:v3.24from 3.0.0 · fixed in 2.7.3-r0
  • rubyAlpine:v3.23from 3.0.0 · fixed in 2.7.3-r0
  • rubyAlpine:v3.22from 3.0.0 · fixed in 2.7.3-r0
  • rubyAlpine:v3.21from 3.0.0 · fixed in 2.7.3-r0
  • rubyAlpine:v3.20from 3.0.0 · fixed in 2.7.3-r0
  • rubyAlpine:v3.19from 3.0.0 · fixed in 2.7.3-r0
  • rubyAlpine:v3.18from 3.0.0 · fixed in 2.7.3-r0

8 more package ranges on OSV.dev

Full record on NVD

Fix

  1. Update Ruby to 3.0.1 · 2.7.3

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • NVDCVSS 3.17.5read 2026-10-23
  • NVDCVSS 2.05read 2026-10-23
  • NVDweakness (CWE)CWE-22read 2026-10-23
  • FIRST EPSSEPSS score58.0 %read 2026-11-09
  • OSVaffected packages—
  • GitHub AdvisoriesadvisoryHIGH2021-05-06

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Published
2021-07-30
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-46f2-3v63-3xrp

Frequently asked questions

What is CVE-2021-28966?

In Ruby through 3.0 on Windows, a remote attacker can submit a crafted path when a Web application handles a parameter with TmpDir.

Is CVE-2021-28966 actively exploited?

Active exploitation of CVE-2021-28966 has not been confirmed. Its EPSS score was 58.0% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-28966?

CVE-2021-28966 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

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