🛡️ CVE-2026-4878 on Debian — libcap2

⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

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.

Distribution advisory

This page covers CVE-2026-4878 as tracked by Debian, for the package libcap2. The fix is available in version 1:2.78-1; earlier versions remain affected.

How this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is high, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

Weakness class

DEBIAN-CVE-2026-4878 is classified as CWE-367: Time-of-check Time-of-use Race Condition. The state checked and the state acted upon can differ, because it may change between the two steps.

Affected software

DEBIAN-CVE-2026-4878 is recorded against 1 package.

  • libcap2 (fixed in 1:2.78-1)

Timeline and source

Published on 9 April 2026 and last revised on 11 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

security-tracker.debian.org (Advisory)

CVE-2026-4878 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2026-04-09
Updated 2026-08-12
Modified 2026-08-11
Fix URL N/A

Affected Packages

Software From version Fixed in
libcap2 — 1:2.78-1

Similar Threats

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