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Fencer Vulns
low 3.3

CVE-2021-23357 json

Directory Traversal

published 2021-03-15 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-10427

cvss
3.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 44%
public exploits
0
none known

Summary

All versions of package github.com/tyktechnologies/tyk/gateway are vulnerable to Directory Traversal via the handleAddOrUpdateApi function. This function is able to delete arbitrary JSON files on the disk where Tyk is running via the management API. The APIID is provided by the user and this value is then used to create a file on disk. If there is a file found with the same name then it will be deleted and then re-created with the contents of the API creation request.

Exploit prediction

0.53% chance of exploitation in the next 30 days, higher than 44% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/TykTechnologies/tyk/issues/3390 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 3.3 CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N
NVD 3.1 5.3 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
NVD 2.0 4.6 AV:L/AC:L/Au:N/C:P/I:P/A:P

Affected products

  • n/a github.com/TykTechnologies/tyk/gateway

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.