Is CVE-2026-100621 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-100621 being exploited in the wild.

How severe is CVE-2026-100621?

Medium severity, with a CVSS score of 4.3, published 26 September 2026.

Is there a fix for CVE-2026-100621?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-100621 attacked?

It is attacked over the network, in a hosted service.

Am I affected by CVE-2026-100621?

Check whether you run Cap-go Capgo at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-100621: Capgo content-lock bypass via r2-direct bundle mutation

CVE-2026-100621 · Severity: medium · CVSS 4.3 · Published 2026-09-26

Capgo is a mobile app update management platform that controls which versions of applications are delivered to devices. An attacker with API write permissions can bypass content-integrity protections by keeping bundle versions in an incomplete state, then modifying critical metadata like checksums and encryption keys before the version is delivered to devices. This allows tampering with app updates without detection, potentially enabling malware distribution or application compromise.

Technologies: Cap-go Capgo. Vendors: Cap-go.

Quick answers

Is CVE-2026-100621 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-100621 being exploited in the wild.
How severe is CVE-2026-100621?: Medium severity, with a CVSS score of 4.3, published 26 September 2026.
Which products and versions are affected?: Cap-go Capgo all.
Is there a fix for CVE-2026-100621?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-100621 attacked?: It is attacked over the network, in a hosted service.
Am I affected by CVE-2026-100621?: Check whether you run Cap-go Capgo at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The vulnerability stems from a flawed content-lock trigger that exempts rows with storage_provider='r2-direct' from mutation protection, combined with the /updates endpoint failing to filter out such rows when selecting versions for delivery. An authenticated attacker with bundle upload permissions can create or retain a version in the r2-direct state, assign it to a distribution channel, then mutate delivery-critical fields (checksum, session_key, name, app_id, r2_path, external_url, manifest, native_packages) via direct database requests. The changes are served to devices through /updates without validation, bypassing previous metadata-tampering mitigations.

Affected products

Cap-go capgo all

Timeline

2026-09-26: disclosed
2026-09-09: advisory: GitHub Security Advisory GHSA-5rg9-rhwj-wj76 published

References

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.