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Fencer Vulns
high 7.5

CVE-2021-36763 json

In CODESYS V3 web server before 3.5.17.10, files or directories are accessible to External Parties.

published 2021-08-03 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-23351

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.2%
EPSS 1.2% chance of exploitation in 30 days, percentile 68%
public exploits
0
none known

Summary

In CODESYS V3 web server before 3.5.17.10, files or directories are accessible to External Parties.

Patch / fix

  • codesys control 4.2.0.0
  • codesys control_rte 3.5.17.10
  • codesys control_runtime_system_toolkit 3.5.17.10
  • codesys control_win_sl 3.5.17.10
  • codesys embedded_target_visu_toolkit 3.5.17.10
  • codesys hmi 3.5.17.10
  • codesys remote_target_visu_toolkit 3.5.17.10

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-26-076-01 updated cvss 7.5

CODESYS in Festo Automation Suite

  • CODESYS Development System 3.0 Festo Automation Suite 2.8.0.137, Festo Automation Suite < 2.8.0.138 CODESYS Development System 3.5.16.10 Festo Automation Suite 2.8.0.137, Festo Automation Suite < 2.8.0.138
    affected: mitigation
  • Festo Automation Suite 2.8.0.138 CODESYS Development System 3.5.21.20
    fixed

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

cisa ICSA-25-273-04 updated cvss 7.5

Festo Controller CECC-S,-LK,-D Family Firmware (Update A)

  • Festo Firmware (R05 (17.06.2016) = 2.3.8.0) installed on Festo Hardware Controller CECC-D (All versions) Festo Firmware (R05 (17.06.2016) = 2.3.8.0) installed on Festo Hardware Controller CECC-S (All versions) Festo Firmware (R06 (11.10.2016) = 2.3.8.1) installed on Festo Hardware Controller CECC-LK (All versions) Festo Firmware (R06 (11.10.2016) = 2.3.8.1) installed on Festo Hardware Controller CECC-S (All versions)
    affected: mitigation “Festo has identified the following specific workarounds and mitigations users can apply to reduce risk:” certvde.com

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

Exploit prediction

1.21% chance of exploitation in the next 30 days, higher than 68% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:P/I:N/A:N

Classification

Weakness
  • CWE-552 Files or Directories Accessible to External Parties

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.