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Fencer Vulns
medium 6.7

CVE-2026-4878 json

Libcap: libcap: privilege escalation via toctou race condition in cap_set_file()

published 2026-04-09 7 mo ago modified 2026-11-04 4 d ago also EUVD-2026-20910

cvss
6.7
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 11%
public exploits
0
none known

Summary

A flaw was found in libcap. A local unprivileged user can exploit a Time-of-check-to-time-of-use (TOCTOU) race condition in the `cap_set_file()` function. This allows an attacker with write access to a parent directory to redirect file capability updates to an attacker-controlled file. By doing so, capabilities can be injected into or stripped from unintended executables, leading to privilege escalation.

Patch / fix

  • Red Hat Red Hat Enterprise Linux 10 0:2.69-7.el10_1.1, 0:2.69-7.el10_2.1
  • Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support 0:2.69-7.el10_0.1
  • Red Hat Red Hat Enterprise Linux 8 0:2.48-6.el8_10.1
  • Red Hat Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support 0:2.48-4.el8_6.1
  • Red Hat Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On 0:2.48-4.el8_6.1
  • Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service 0:2.48-5.el8_8.1
  • Red Hat Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions 0:2.48-5.el8_8.1
  • Red Hat Red Hat Enterprise Linux 9 0:2.48-10.el9_7.1, 0:2.48-10.el9_8.1
  • Red Hat Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions 0:2.48-9.el9_2.1
  • Red Hat Red Hat Enterprise Linux 9.4 Extended Update Support 0:2.48-9.el9_4.1
  • Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support 0:2.48-9.el9_6.1
  • Red Hat Red Hat OpenShift Container Platform 4.12 412.86.202608241157-0
  • Red Hat Red Hat OpenShift Container Platform 4.13 413.92.202606160406-0
  • Red Hat Red Hat OpenShift Container Platform 4.14 414.92.202606231112-0
  • Red Hat Red Hat OpenShift Container Platform 4.15 415.92.202606030318-0
  • Red Hat Red Hat OpenShift Container Platform 4.16 416.94.202606051757-0
  • Red Hat Red Hat OpenShift Container Platform 4.17 417.94.202606250942-0
  • Red Hat Red Hat OpenShift Container Platform 4.18 418.94.202606051320-0
  • Red Hat Red Hat OpenShift Container Platform 4.19 4.19.9.6.202606031700-0
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.17 1791371069, 1791371080, 1791788287, 1791970484
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.18 1789029076, 1791459707, 1791459711, 1791459759, 1791966259
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.20 1790598593
  • Red Hat Cost Management 4 1780946239, 1783539156
  • Red Hat Red Hat AI Inference Server 3.2 1780681984
  • Red Hat Red Hat AI Inference Server 3.3 1782352847, 1782352919, 1782352950, 1782353093
  • Red Hat Red Hat Discovery 2 1778101579, 1778156756, 1782159791, 1782166952
  • Red Hat Red Hat Hardened Images 2.78-1.1.hum1
  • Red Hat Red Hat Insights proxy 1.5 1780420428
  • Red Hat Red Hat OpenShift AI 3.4 1790703542
  • Red Hat Red Hat OpenShift distributed tracing 3.9.3 1778056233, 1778056245, 1778056267
  • libcap2 Debian 12 1:2.66-4+deb12u3
  • libcap2 Debian 13 1:2.75-10+deb13u1
  • libcap2 Debian 14 1:2.78-1

debian advisories DEBIAN-CVE-2026-4878

  • libcap2 Ubuntu 22.04 LTS 1:2.44-1ubuntu0.22.04.3
  • libcap2 Ubuntu 24.04 LTS 1:2.66-5ubuntu2.4
  • libcap2 Ubuntu 25.10 1:2.75-7ubuntu2.2
  • libcap2 Ubuntu Pro 14.04 LTS 1:2.24-0ubuntu2+esm2
  • libcap2 Ubuntu Pro 16.04 LTS 1:2.24-12ubuntu0.1~esm2
  • libcap2 Ubuntu Pro 18.04 LTS 1:2.25-1.2ubuntu0.1~esm2
  • libcap2 Ubuntu Pro 20.04 LTS 1:2.32-1ubuntu0.2+esm1

ubuntu advisories UBUNTU-CVE-2026-4878

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

  • libcap RHEL 9 2.48-10.el9_8.1
  • libcap RHEL 10.2 2.69-7.el10_2.1
  • libcap RHEL 8 2.48-6.el8_10.1
  • libcap RHEL 9 2.48-10.el9_7.1
  • libcap RHEL 10.1 2.69-7.el10_1.1
  • libcap hummingbird 1 2.78-1.1.hum1
  • libcap RHEL 8.6 EUS_LONG_LIFE, RHEL 8.6 AUS 2.48-4.el8_6.1
  • libcap RHEL 8.8 TUS, RHEL 8.8 E4S 2.48-5.el8_8.1

red hat advisories RHSA-2026:24346RHSA-2026:22957RHSA-2026:21254RHSA-2026:20595RHSA-2026:19458RHSA-2026:19456

  • libcap Linux Micro 6.2 2.73-160000.3.1
  • libcap Linux Micro 6.1 2.69-slfo.1.1_2.1
  • libcap Linux Micro 6.0 2.69-3.1
  • libcap SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +11 more 2.63-150400.3.6.1
  • libcap SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 2.26-14.12.1

suse advisories SUSE-SU-2026:21274-1SUSE-SU-2026:21257-1SUSE-SU-2026:21243-1SUSE-SU-2026:1433-1SUSE-SU-2026:1432-1

  • libcap openSUSE Leap 16.0 2.73-160000.3.1
  • libcap openSUSE Tumbleweed 2.78-1.1

opensuse advisories openSUSE-SU-2026:20613-1openSUSE-SU-2026:10536-1

  • libcap AlmaLinux 10 2.69-7.el10_2.1
  • libcap AlmaLinux 9 2.48-10.el9_8.1
  • libcap AlmaLinux 8 2.48-6.el8_10.1
  • libcap AlmaLinux 10 2.69-7.el10_1.1
  • libcap AlmaLinux 9 2.48-10.el9_7.1

almalinux advisories ALSA-2026:19130ALSA-2026:19346ALSA-2026:13285ALSA-2026:12423ALSA-2026:12441

  • libcap Rocky Linux 10 2.69-7.el10_1.1
  • libcap Rocky Linux 9 2.48-10.el9_7.1
  • libcap Rocky Linux 8 2.48-6.el8_10.1

rocky linux advisories RLSA-2026:19130RLSA-2026:19346RLSA-2026:13285RLSA-2026:12423RLSA-2026:12441

  • libcap Alpine 3.24, Alpine 3.23, Alpine 3.22 +2 more 2.78-r0

alpine advisories ALPINE-CVE-2026-4878

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libcap Azure Linux 3.0 2.69-14

azure linux advisories AZL-82425

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-2026-4878 updated cvss 6.7

libcap: libcap: Privilege escalation via TOCTOU race condition in cap_set_file()

  • Red Hat Enterprise Linux 6 libcap, compat-libcap1 Red Hat Enterprise Linux 7 libcap, compat-libcap1
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat OpenShift Container Platform 4 openshift4/ose-hypershift-rhel9
    under investigation
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.17 cert-manager/cert-manager-operator-rhel9 1791788287, cert-manager/jetstack-cert-manager-rhel9 1791371069, cert-manager/cert-manager-operator-bundle 1791970484, cert-manager/jetstack-cert-manager-acmesolver-rhel9 1791371080
    fixed: vendor fix RHSA-2026:82888
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.18 cert-manager/cert-manager-operator-rhel9 1789029076, cert-manager/jetstack-cert-manager-rhel9 1791459711, cert-manager/cert-manager-istio-csr-rhel9 1791459759, cert-manager/cert-manager-operator-bundle 1791966259, cert-manager/jetstack-cert-manager-acmesolver-rhel9 1791459707
    fixed: vendor fix RHSA-2026:82354
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.20 cert-manager/cert-manager-trust-manager-rhel9 1790598593
    fixed: vendor fix RHSA-2026:72502
  • Red Hat Cost Management 4 costmanagement/costmanagement-metrics-rhel9-operator 1780946239, costmanagement/costmanagement-metrics-rhel9-operator 1783539156
    fixed: vendor fix RHSA-2026:39981
  • Red Hat AI Inference Server 3.2 rhaiis/model-opt-cuda-rhel9 1780681984
    fixed: vendor fix RHSA-2026:25096
  • Red Hat AI Inference Server 3.3 rhaiis/vllm-cuda-rhel9 1782352847, rhaiis/vllm-rocm-rhel9 1782353093, rhaiis/vllm-spyre-rhel9 1782352919, rhaiis/model-opt-cuda-rhel9 1782352950
    fixed: vendor fix RHSA-2026:30078
show 31 more
  • Red Hat Discovery 2 discovery 1778101579, discovery 1778156756, discovery/discovery-ui-rhel9 1782166952, discovery/discovery-server-rhel9 1782159791
    fixed: vendor fix RHSA-2026:14937
  • Red Hat Enterprise Linux AppStream (v. 9) libcap-devel 2.48-10.el9_7.1, libcap-devel 2.48-10.el9_8.1, libcap-debuginfo 2.48-10.el9_7.1, libcap-debuginfo 2.48-10.el9_8.1, libcap-debugsource 2.48-10.el9_7.1, libcap-debugsource 2.48-10.el9_8.1
    fixed: vendor fix RHSA-2026:12441
  • Red Hat Enterprise Linux AppStream (v. 10) libcap-devel 2.69-7.el10_1.1, libcap-devel 2.69-7.el10_2.1, libcap-debuginfo 2.69-7.el10_1.1, libcap-debuginfo 2.69-7.el10_2.1, libcap-debugsource 2.69-7.el10_1.1, libcap-debugsource 2.69-7.el10_2.1
    fixed: vendor fix RHSA-2026:12423
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) libcap-devel 2.48-9.el9_2.1, libcap-debuginfo 2.48-9.el9_2.1, libcap-debugsource 2.48-9.el9_2.1
    fixed: vendor fix RHSA-2026:21254
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) libcap-devel 2.69-7.el10_0.1, libcap-debuginfo 2.69-7.el10_0.1, libcap-debugsource 2.69-7.el10_0.1
    fixed: vendor fix RHSA-2026:19456
  • Red Hat Enterprise Linux AppStream EUS (v.9.4) libcap-devel 2.48-9.el9_4.1, libcap-debuginfo 2.48-9.el9_4.1, libcap-debugsource 2.48-9.el9_4.1
    fixed: vendor fix RHSA-2026:20595
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) libcap-devel 2.48-9.el9_6.1, libcap-debuginfo 2.48-9.el9_6.1, libcap-debugsource 2.48-9.el9_6.1
    fixed: vendor fix RHSA-2026:19458
  • Red Hat Enterprise Linux BaseOS (v. 8) libcap 2.48-6.el8_10.1
    fixed: vendor fix RHSA-2026:13285
  • Red Hat Enterprise Linux BaseOS (v. 9) libcap 2.48-10.el9_7.1, libcap 2.48-10.el9_8.1
    fixed: vendor fix RHSA-2026:12441
  • Red Hat Enterprise Linux BaseOS (v. 10) libcap 2.69-7.el10_1.1, libcap 2.69-7.el10_2.1
    fixed: vendor fix RHSA-2026:12423
  • Red Hat Enterprise Linux BaseOS AUS (v.8.6) libcap 2.48-4.el8_6.1
    fixed: vendor fix RHSA-2026:24346
  • Red Hat Enterprise Linux BaseOS E4S (v.8.8) libcap 2.48-5.el8_8.1
    fixed: vendor fix RHSA-2026:22957
  • Red Hat Enterprise Linux BaseOS E4S (v.9.2) libcap 2.48-9.el9_2.1
    fixed: vendor fix RHSA-2026:21254
  • Red Hat Enterprise Linux BaseOS EUS (v. 10.0) libcap 2.69-7.el10_0.1
    fixed: vendor fix RHSA-2026:19456
  • Red Hat Enterprise Linux BaseOS EUS (v.9.4) libcap 2.48-9.el9_4.1
    fixed: vendor fix RHSA-2026:20595
  • Red Hat Enterprise Linux BaseOS EUS (v.9.6) libcap 2.48-9.el9_6.1
    fixed: vendor fix RHSA-2026:19458
  • Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6) libcap 2.48-4.el8_6.1
    fixed: vendor fix RHSA-2026:24346
  • Red Hat Enterprise Linux BaseOS TUS (v.8.8) libcap 2.48-5.el8_8.1
    fixed: vendor fix RHSA-2026:22957
  • Red Hat Hardened Images libcap 2.78-1.1.hum1
    fixed: vendor fix RHSA-2026:7473
  • Red Hat Insights proxy 1.5 insights-proxy/insights-proxy-container-rhel9 1780420428
    fixed: vendor fix RHSA-2026:22634
  • Red Hat OpenShift AI 3.4 rhai/base-image-neuron-rhel9 1790703542
    fixed: vendor fix RHSA-2026:74674
  • Red Hat OpenShift Container Platform 4.12 rhcos 412.86.202608241157
    fixed: vendor fix RHSA-2026:59831
  • Red Hat OpenShift Container Platform 4.13 rhcos 413.92.202606160406
    fixed: vendor fix RHSA-2026:26542
  • Red Hat OpenShift Container Platform 4.14 rhcos 414.92.202606231112
    fixed: vendor fix RHSA-2026:28887
  • Red Hat OpenShift Container Platform 4.15 rhcos 415.92.202606030318
    fixed: vendor fix RHSA-2026:23233
  • Red Hat OpenShift Container Platform 4.16 rhcos 416.94.202606051757
    fixed: vendor fix RHSA-2026:25044
  • Red Hat OpenShift Container Platform 4.17 rhcos 417.94.202606250942
    fixed: vendor fix RHSA-2026:34098
  • Red Hat OpenShift Container Platform 4.18 rhcos 418.94.202606051320
    fixed: vendor fix RHSA-2026:25181
  • Red Hat OpenShift Container Platform 4.19 rhcos 4.19.9.6.202606031700
    fixed: vendor fix RHSA-2026:23245
  • Red Hat OpenShift distributed tracing 3.9.3 rhosdt 1778056233, rhosdt 1778056245, rhosdt 1778056267
    fixed: vendor fix RHSA-2026:14162
  • Red Hat Update Infrastructure 5 rhui5/cds-rhel9 1779798159, rhui5/rhua-rhel9 1779798222, rhui5/haproxy-rhel9 1779798164, rhui5/rhua-tp-rhel9 1787241260, rhui5/installer-rhel9 1779798165, rhui5/installer-tp-rhel9 1787135742, +1 more
    fixed: vendor fix RHSA-2026:58981

4 more not affected in the full advisory

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
total
Assessed
7 mo ago

Exploit prediction

0.21% chance of exploitation in the next 30 days, higher than 11% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • openwall.com http://www.openwall.com/lists/oss-security/2026/04/09/5 referenced PoC, tagged "exploit" by a source, unverified
  • openwall.com http://www.openwall.com/lists/oss-security/2026/04/09/6 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.7 CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H
CISA ADP 3.1 6.7 CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H
NVD 3.1 7.0 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
  • Red Hat Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On
  • Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service
  • Red Hat Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9.4 Extended Update Support
  • Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support
  • Red Hat Red Hat OpenShift Container Platform 4.12
  • Red Hat Red Hat OpenShift Container Platform 4.13
  • Red Hat Red Hat OpenShift Container Platform 4.14
  • Red Hat Red Hat OpenShift Container Platform 4.15
  • Red Hat Red Hat OpenShift Container Platform 4.16
  • Red Hat Red Hat OpenShift Container Platform 4.17
  • Red Hat Red Hat OpenShift Container Platform 4.18
  • Red Hat Red Hat OpenShift Container Platform 4.19
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.17
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.18
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.20
  • Red Hat Cost Management 4
  • Red Hat Red Hat AI Inference Server 3.2
  • Red Hat Red Hat AI Inference Server 3.3
  • Red Hat Red Hat Discovery 2
  • Red Hat Red Hat Hardened Images
  • Red Hat Red Hat Insights proxy 1.5
  • Red Hat Red Hat OpenShift AI 3.4
  • Red Hat Red Hat OpenShift distributed tracing 3.9.3
  • Red Hat Red Hat Update Infrastructure 5
  • Red Hat Red Hat Enterprise Linux 6
  • Red Hat Red Hat Enterprise Linux 7
  • Red Hat Red Hat OpenShift Container Platform 4

Classification

Weakness
  • CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition

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.