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Fencer Vulns
high 8.8

CVE-2026-23742 json

Skipper arbitrary code execution through lua filters

published 2026-01-16 9 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-2860 , GHSA-cc8m-98fm-rc9g , GO-2026-4327

cvss
8.8
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

Skipper is an HTTP router and reverse proxy for service composition. The default skipper configuration before 0.23.0 was -lua-sources=inline,file. The problem starts if untrusted users can create lua filters, because of -lua-sources=inline , for example through a Kubernetes Ingress resource. The configuration inline allows these user to create a script that is able to read the filesystem accessible to the skipper process and if the user has access to read the logs, they an read skipper secrets. This vulnerability is fixed in 0.23.0.

Patch / fix

  • go github.com/zalando/skipper 0.23.0
  • zalando skipper 0.23.0
  • govulncheck-vulndb openSUSE Leap 15.6 0.0.20260205T172317-150000.1.146.1

suse advisories SUSE-SU-2026:0403-1

  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
9 mo ago

Exploit prediction

0.51% 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/zalando/skipper/security/advisories/GHSA-cc8m-98fm-rc9g referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
GitHub 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
go github.com/zalando/skipper
<0.23.0
0.23.0

Affected products

  • zalando skipper

Classification

Weakness
  • CWE-94 Improper Control of Generation of Code
  • CWE-250 Execution with Unnecessary Privileges
  • CWE-522 Insufficiently Protected Credentials

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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.