# CVE-2026-123870: [Eclipse CSI - otterdog] Unauthenticated remote code execution via eval() on format-string-injected webhook body when GITHUB_WEBHOOK_SECRET is unset

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

The otterdog webapp evaluates a format-string built from the incoming GitHub webhook JSON body using Python's eval(). When the GITHUB_WEBHOOK_SECRET configuration value is unset or empty (the code default is None), the HMAC signature check is skipped entirely, allowing an unauthenticated network client to reach the eval() sink with attacker-controlled input and execute arbitrary Python on the webapp host.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Eclipse Foundation / otterdog (otterdog): ≥ 0.9.0; < 1.3.2 (affected, semver); 1.3.2 (unaffected). Source: CNA: eclipse

## Severity and prioritization

- CVSS 4.0: 9.5 (critical); CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H; source: CNA: eclipse

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-95

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://gitlab.eclipse.org/security/cve-assignment/-/work_items/554 (CNA: eclipse)

- https://github.com/eclipse-csi/otterdog/security/advisories/GHSA-32xf-7j44-xq72 (CNA: eclipse)

- https://github.com/eclipse-csi/otterdog/commit/bbc9e3ced3665f09fc4632f11b5867524eda7f72 (CNA: eclipse)

## Provenance

- CNA: eclipse: https://www.cve.org/CVERecord?id=CVE-2026-123870; retrieved 2026-11-09; source updated 2026-11-09

Revision: e4dffea58869797eab56e47ad9fe38209b931d82064524562eb8e7a77ad634ec

Canonical: https://y2.dev/cve/CVE-2026-123870

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