# CVE-2026-6862: Efivar: efivar: denial of service due to stack overflow in device path node parsing

Status: published. Published: 2026-04-22. Updated: 2026-11-05.

A flaw was found in libefiboot, a component of efivar. The device path node parser in libefiboot fails to validate that each node's Length field is at least 4 bytes, which is the minimum size for an EFI (Extensible Firmware Interface) device path node header. A local user could exploit this vulnerability by providing a specially crafted device path node. This can lead to infinite recursion, causing stack exhaustion and a process crash, resulting in a denial of service (DoS).

## Remediation

- workaround: Applications using efi_loadopt_is_valid() should validate the size of the input buffer before passing it to libefiboot. As a library-level fix, the device path iterator should enforce a minimum node Length of 4 before recursing:

  if (dp->length < 4)
      return -1; (source: CNA: redhat)

## Affected products and versions

- Red Hat / Red Hat Hardened Images (efivar-main): ≥ 39-13.1.hum1; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 10 (efivar): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 (efivar): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (efivar): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (efivar): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 4 (openshift/ose-rhel-coreos-8): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 4 (openshift/ose-rhel-coreos-9): Version range not reported. Source: CNA: redhat

## Severity and prioritization

- CVSS 3.1: 5.5 (medium); CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H; source: CNA: redhat

- CISA KEV: No listing in collected sources

- EPSS: 0.12% as of 2026-11-05; percentile 1.65%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-674

## Exploit evidence

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

## References

- https://access.redhat.com/errata/RHSA-2026:69321 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/security/cve/CVE-2026-6862 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2459982 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2026-6862; retrieved 2026-11-05; source updated 2026-11-05

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-6862; retrieved 2026-11-05; source updated Not reported

Revision: bd540dda7f4e44539d37f6ac696479ddb597a2e398d26d2f6442545a9ec21135

Canonical: https://y2.dev/cve/CVE-2026-6862

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