# CVE-2026-123370: compose-lint: `fix --apply` can delete a line the user did not select, including a security setting

Status: published. Published: 2026-11-09. Updated: 2026-11-14.

compose-lint is a Docker Compose security linter that identifies dangerous misconfigurations before deployment. From 0.9.0 until 0.18.0, compose-lint's YAML parser recognizes lone carriage returns and Unicode line separators U+0085, U+2028, and U+2029 as line breaks while fix position conversion counts only newline characters. A pull request can place one of these separators in a quoted value so fix --apply shifts each later edit and deletes the line after the selected target, including an unselected network or other security setting. The resulting Compose file can remain valid, post-edit checks can pass, and the command can report a successful fix even though the dry-run diff was the only place showing the extra deletion. This issue is fixed in version 0.18.0.

## Remediation

- fix: compose-lint (pip): GitHub reports patched versions 0.18.0. Check the advisory for the affected release branch. (source: GitHub GHSA-65v8-q222-64xx) — https://github.com/tmatens/compose-lint/security/advisories/GHSA-65v8-q222-64xx
- fix: compose-lint (PyPI): OSV reports a fixed version 0.18.0. Check the advisory for supported release branches. (source: OSV GHSA-65v8-q222-64xx) — https://github.com/advisories/GHSA-65v8-q222-64xx

## Affected products and versions

- tmatens / compose-lint: >= 0.9.0, < 0.18.0 (affected). Source: CNA: GitHub_M
-  / compose-lint (compose-lint): >= 0.9.0, <= 0.17.0 (affected, GitHub advisory range). Source: GitHub GHSA-65v8-q222-64xx
-  / compose-lint (compose-lint): 0.10.0 (affected, PyPI); 0.11.0 (affected, PyPI); 0.12.0 (affected, PyPI); 0.12.1 (affected, PyPI); 0.12.2 (affected, PyPI); 0.13.0 (affected, PyPI); 0.14.0 (affected, PyPI); 0.14.1 (affected, PyPI); 0.15.0 (affected, PyPI); 0.15.1 (affected, PyPI); 0.15.2 (affected, PyPI); 0.16.0 (affected, PyPI); 0.17.0 (affected, PyPI); 0.9.0 (affected, PyPI); Ecosystem version events: introduced 0.9.0; fixed 0.18.0. Source: OSV GHSA-65v8-q222-64xx

## Severity and prioritization

- CVSS 4.0: 5.1 (medium); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N; source: CNA: GitHub_M

- CVSS 4.0: 5.1 (medium); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: security-advisories@github.com

- CISA KEV: No listing in collected sources

- EPSS: 0.33% as of 2026-11-13; percentile 26.56%

- SSVC: exploitation poc; automatable yes; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-193

## Exploit evidence

- exploit: https://github.com/tmatens/compose-lint/security/advisories/GHSA-65v8-q222-64xx (ADP: CISA-ADP)

## References

- https://github.com/tmatens/compose-lint/security/advisories/GHSA-65v8-q222-64xx (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/tmatens/compose-lint/pull/547 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/tmatens/compose-lint/pull/549 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/tmatens/compose-lint/commit/c9d453a6a69c076788fe1db05cb54684a616d1de (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/tmatens/compose-lint/commit/cbbf886d91347dea9c51b584eb50088e70007d0d (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/tmatens/compose-lint/releases/tag/v0.18.0 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/tmatens/compose-lint/security/advisories/GHSA-65v8-q222-64xx (ADP: CISA-ADP; exploit)

- https://github.com/tmatens/compose-lint/commit/c9d453a6a69c076788fe1db05cb54684a616d1de (security-advisories@github.com)

- https://github.com/tmatens/compose-lint/commit/cbbf886d91347dea9c51b584eb50088e70007d0d (security-advisories@github.com)

- https://github.com/tmatens/compose-lint/pull/547 (security-advisories@github.com)

- https://github.com/tmatens/compose-lint/pull/549 (security-advisories@github.com)

- https://github.com/tmatens/compose-lint/releases/tag/v0.18.0 (security-advisories@github.com)

- https://github.com/tmatens/compose-lint/security/advisories/GHSA-65v8-q222-64xx (security-advisories@github.com)

- https://github.com/tmatens/compose-lint/security/advisories/GHSA-65v8-q222-64xx (GitHub Security Advisories; advisory)

- https://github.com/advisories/GHSA-65v8-q222-64xx (OSV / GitHub Security Advisories; advisory)

- https://osv.dev/vulnerability/GHSA-65v8-q222-64xx (OSV / GitHub Security Advisories; osv)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-123370; retrieved 2026-11-14; source updated 2026-11-14

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-123370; retrieved 2026-11-13; source updated 2026-11-12

- GitHub Security Advisories: https://github.com/tmatens/compose-lint/security/advisories/GHSA-65v8-q222-64xx; retrieved 2026-11-12; source updated 2026-11-09

- OSV / GitHub Security Advisories: https://osv.dev/vulnerability/GHSA-65v8-q222-64xx; retrieved 2026-11-14; source updated 2026-11-10

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-123370; retrieved 2026-11-14; source updated Not reported

Revision: 1a357d7e7152d4dde9335583138bf0357b91dd8ab85293604af233a4ba71ab4e

Canonical: https://y2.dev/cve/CVE-2026-123370

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