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Fencer Vulns
medium 6.2

CVE-2026-18938 json

P11-kit: integer overflow in rpc attribute-array length calculation can under-allocate nested attribute storage on 32 bit systems

published 2026-08-07 3 mo ago modified 2026-08-14 2 mo ago also EUVD-2026-54413

cvss
6.2
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 1%
public exploits
0
none known

Summary

A flaw was found in p11-kit. A local attacker, or one with equivalent access to a reachable RPC channel, could exploit an integer overflow vulnerability. By sending specially crafted messages, the attacker can cause the system to miscalculate memory allocation for nested attributes. This leads to a memory corruption issue, specifically a heap out-of-bounds write, which can crash the p11-kit RPC parsing process, resulting in a Denial of Service (DoS). This vulnerability is only exploitable on 32 bit systems.

Patch / fix

  • p11-kit Debian 14 0.26.5-1

debian advisories DEBIAN-CVE-2026-18938

  • p11-kit Ubuntu 22.04 LTS 0.24.0-6ubuntu0.1
  • p11-kit Ubuntu 24.04 LTS 0.25.3-4ubuntu2.2
  • p11-kit Ubuntu Pro 18.04 LTS 0.23.9-2ubuntu0.1+esm1
  • p11-kit Ubuntu Pro 20.04 LTS 0.23.20-1ubuntu0.1+esm1

ubuntu advisories UBUNTU-CVE-2026-18938

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • p11-kit SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 0.25.5-160000.3.1

suse advisories SUSE-SU-2026:24193-1SUSE-SU-2026:24255-1

  • p11-kit openSUSE Leap 16.0 0.25.5-160000.3.1
  • p11-kit openSUSE Tumbleweed 0.26.5-1.1

opensuse advisories openSUSE-SU-2026:22105-1openSUSE-SU-2026:11862-1

  • p11-kit Azure Linux 3.0 0.26.5-1

azure linux advisories AZL-95481

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-18938 updated cvss 6.2

p11-kit: Integer overflow in RPC attribute-array length calculation can under-allocate nested attribute storage on 32 bit systems

  • Red Hat Enterprise Linux 6 p11-kit, p11-kit-trust Red Hat Enterprise Linux 7 p11-kit, p11-kit-trust Red Hat Enterprise Linux 8 p11-kit, p11-kit-trust, p11-kit-server Red Hat Enterprise Linux 9 p11-kit, p11-kit-trust, p11-kit-client, p11-kit-server Red Hat Enterprise Linux 10 p11-kit Red Hat Hardened Images p11-kit
    +2 more products
    Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

0.11% chance of exploitation in the next 30 days, higher than 1% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.2 CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 6
  • Red Hat Red Hat Enterprise Linux 7
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat Hardened Images
  • Red Hat Red Hat OpenShift Container Platform 4

Classification

Weakness
  • CWE-122 Heap-based Buffer Overflow

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.