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No exploitation reportedFix available

CVE-2026-118599

epiphany: TAR-based .xpi with hard links can overwrite user files during WebExtension install

No exploitation reported by the sources we read.

  • Published2026-10-31
  • WeaknessCWE-59

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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

Timeline

dates in UTC
  1. 2026-10-3109:29CVE publishedCNA

Versions per branch

Products declared by the CNA1 product

As fedora, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-10-31

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • epiphanyopenSUSE:Tumbleweedall versions · fixed in 51.2-1.1
  • epiphany-browserUbuntu:26.10all versions · no fixed version listed
  • epiphany-browserUbuntu:26.04:LTSall versions · no fixed version listed
  • epiphany-browserUbuntu:24.04:LTSall versions · no fixed version listed
  • epiphany-browserUbuntu:22.04:LTSall versions · no fixed version listed
  • epiphany-browserUbuntu:20.04:LTSall versions · no fixed version listed
  • epiphany-browserUbuntu:18.04:LTSall versions · no fixed version listed
  • epiphany-browserUbuntu:16.04:LTSall versions · no fixed version listed

3 more package ranges on OSV.dev

Vendor advisories

  • CVE-2026-118599 Red Hat Product Security

    epiphany: epiphany: TAR-based .xpi with hard links can overwrite user files during WebExtension install

Full record on NVD

Fix

No fix published by the sources we read yet. NVD record

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
Published
2026-10-31
Last Modified
2026-11-06
NVD status
Deferred
GitHub Advisory
GHSA-h27g-h5mg-6hm2

Frequently asked questions

What is 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

Is CVE-2026-118599 actively exploited?

Active exploitation of CVE-2026-118599 has not been confirmed. Its EPSS score was 0.2% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-118599?

CVE-2026-118599 has a CVSS v3 base score of 5.5 (MEDIUM severity), with vector string CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N.

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