# CVE-2026-42015: GnuTLS off-by-one error in PKCS#12 bag element bounds check

Source: https://junglewise.ai/threats/cve-2026-42015-gnutls-off-by-one-error-in-pkcs-12-bag-element-bounds-check  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-26. Updated: 2026-05-26  
License: CC BY 4.0 with a link back

CVE-2026-42015 · Severity: medium · CVSS 5.3 · Published 2026-05-26

A security flaw has been identified in GnuTLS, a widely used library that enables secure communication for many applications and operating systems. The vulnerability occurs when the software processes specifically formatted digital certificate files (PKCS#12), potentially allowing an attacker to crash the application or service using the library. This could lead to a denial of service, disrupting business operations that rely on secure network connections.

Technologies: [Red Hat Enterprise Linux 10](https://junglewise.ai/threats/technologies/enterprise-linux-10), [Red Hat Enterprise Linux 8](https://junglewise.ai/threats/technologies/enterprise-linux-8), [Red Hat Enterprise Linux 9](https://junglewise.ai/threats/technologies/enterprise-linux-9). Vendors: [Red Hat](https://junglewise.ai/threats/vendors/red-hat).

## Quick answers

**Is CVE-2026-42015 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-42015 being exploited in the wild.

**How severe is CVE-2026-42015?** Medium severity, with a CVSS score of 5.3, published 26 May 2026.

**Which products and versions are affected?** GnuTLS gnutls; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9; Red Hat Enterprise Linux 10.

**Is there a fix for CVE-2026-42015?** A patch was published on 2026-05-26: Red Hat released security advisories for RHEL 8, 9, and 10 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-42015 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-42015?** Check whether you run Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8 or Red Hat Enterprise Linux 9. 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

An off-by-one error (CWE-193) exists in GnuTLS within the PKCS#12 bag element bounds checking logic. When an application attempts to append an element to a PKCS#12 bag that already contains 32 elements, the library fails to properly validate the array boundaries, resulting in a write past the internal array. This memory corruption can be triggered by a remote attacker providing a malformed PKCS#12 structure. The primary impact is a denial of service (DoS) via application crash, though other unspecified impacts resulting from memory corruption cannot be entirely ruled out. Red Hat has released security advisories (RHSA-2026:20611, RHSA-2026:20612, RHSA-2026:20613) to address this in Enterprise Linux versions 8, 9, and 10.

## Affected products

- GnuTLS gnutls
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat Enterprise Linux 10

## Timeline

- 2026-05-07: disclosed: Reported by Zou Dikai via Red Hat Bugzilla
- 2026-05-26: patched: Red Hat released security advisories for RHEL 8, 9, and 10
- 2026-05-26: advisory: NVD published CVE-2026-42015

## References

- [https://access.redhat.com/security/cve/CVE-2026-42015](https://access.redhat.com/security/cve/CVE-2026-42015)
- [https://bugzilla.redhat.com/show_bug.cgi?id=2467678](https://bugzilla.redhat.com/show_bug.cgi?id=2467678)

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