Vulnerability in GNOME Epiphany
CVE-2026-118599
A file overwrite vulnerability exists in Epiphany when installing WebExtension packages from .xpi files. In src/webextension/ephy-web-extension-manager.c, decompress_xpi_thread() used libarchive with archive_read_support_format_all() (and filters), so the installer did not require a real ZIP. A TAR file named *.xpi was extracted. TAR supports hard-link entry types; with Epiphany's archive_write_disk options (including ARCHIVE_EXTRACT_PERM), a crafted hard-link target can cause an attacker-chosen existing user-writable file to be truncated and overwritten with attacker-controlled content and mode bits, without a dedicated warning dialog, when the user installs or opens the crafted .xpi. This is related to but separate from the ZIP-slip path traversal fixed as CVE-2026-77679 (#2922 / MR !2143). Requirements: the victim must install or open a malicious WebExtension (.xpi). Affected: Epiphany >= 47.0 (WebExtension XPI install path). Fixed: https://gitlab.gnome.org/GNOME/epiphany/-/merge_requests/2248 (commit 0cc9ab55 — only enable ZIP format support). Upstream: https://gitlab.gnome.org/GNOME/epiphany/-/work_items/2988 Reporter acknowledgment: Fernando Munoz
Published .
CVSS v3 metric
CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N.
EPSS exploit prediction
EPSS: 0.002 (7.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 8th percentile — 7.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
The 30-day trend appears once there are two daily scores.
Affected products
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-118599?
- CVE-2026-118599 is a medium-severity vulnerability in GNOME Epiphany, classified under Improper Link Resolution Before File Access. CVSS score: 5.5/10. Published 2026-10-31.
- How severe is CVE-2026-118599?
- Medium severity. CVSS v3 base score is 5.5 out of 10.