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

CVSS v3 5.5 MEDIUM

5.5^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 1.8 / Impact : 3.6

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact NONE

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://access.redhat.com/security/cve/CVE-2026-118599
https://bugzilla.redhat.com/show_bug.cgi?id=2562969
https://gitlab.gnome.org/GNOME/epiphany/-/merge_requests/2248
https://gitlab.gnome.org/GNOME/epiphany/-/work_items/2988

Configurations

No configuration.

History

31 Oct 2026, 10:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-31 10:16

Updated : 2026-10-31 10:16

NVD link : CVE-2026-118599

Mitre link : CVE-2026-118599

CVE.ORG link : CVE-2026-118599

JSON object : View

Products Affected

No product.

CWE

CWE-59

Improper Link Resolution Before File Access ('Link Following')

{"id": "CVE-2026-118599", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Secondary", "source": "patrick@puiterwijk.org", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.5, "attackVector": "LOCAL", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N", "integrityImpact": "HIGH", "userInteraction": "REQUIRED", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 1.8}]}, "affected": [{"source": "patrick@puiterwijk.org", "affectedData": [{"vendor": "GNOME", "product": "Epiphany", "versions": [{"status": "affected", "version": "47.0", "lessThan": "*", "versionType": "semver"}], "packageName": "epiphany", "collectionURL": "https://gitlab.gnome.org/GNOME/epiphany", "defaultStatus": "unaffected"}]}], "published": "2026-10-31T10:16:38.060", "references": [{"url": "https://access.redhat.com/security/cve/CVE-2026-118599", "source": "patrick@puiterwijk.org"}, {"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2562969", "source": "patrick@puiterwijk.org"}, {"url": "https://gitlab.gnome.org/GNOME/epiphany/-/merge_requests/2248", "source": "patrick@puiterwijk.org"}, {"url": "https://gitlab.gnome.org/GNOME/epiphany/-/work_items/2988", "source": "patrick@puiterwijk.org"}], "vulnStatus": "Received", "weaknesses": [{"type": "Secondary", "source": "patrick@puiterwijk.org", "description": [{"lang": "en", "value": "CWE-59"}]}], "descriptions": [{"lang": "en", "value": "A file overwrite vulnerability exists in Epiphany when installing WebExtension packages from .xpi files.\n\nIn 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.\n\nThis is related to but separate from the ZIP-slip path traversal fixed as CVE-2026-77679 (#2922 / MR !2143).\n\nRequirements: the victim must install or open a malicious WebExtension (.xpi).\n\nAffected: Epiphany >= 47.0 (WebExtension XPI install path).\nFixed: https://gitlab.gnome.org/GNOME/epiphany/-/merge_requests/2248 (commit 0cc9ab55 \u2014 only enable ZIP format support).\nUpstream: https://gitlab.gnome.org/GNOME/epiphany/-/work_items/2988\nReporter acknowledgment: Fernando Munoz"}], "lastModified": "2026-10-31T10:16:38.060", "sourceIdentifier": "patrick@puiterwijk.org"}