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GHSA-H27G-H5MG-6HM2

Vulnerability from github – Published: 2026-10-31 12:31 – Updated: 2026-10-31 12:31

Details

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

Severity

5.5 (Medium)


                  
                    CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

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{
  "affected": [],
  "aliases": [
    "CVE-2026-118599"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-59"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-31T10:16:38Z",
    "severity": "MODERATE"
  },
  "details": "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\u0027s 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 \u003e= 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",
  "id": "GHSA-h27g-h5mg-6hm2",
  "modified": "2026-10-31T12:31:16Z",
  "published": "2026-10-31T12:31:15Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-118599"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2026-118599"
    },
    {
      "type": "WEB",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2562969"
    },
    {
      "type": "WEB",
      "url": "https://gitlab.gnome.org/GNOME/epiphany/-/merge_requests/2248"
    },
    {
      "type": "WEB",
      "url": "https://gitlab.gnome.org/GNOME/epiphany/-/work_items/2988"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-118599 (GCVE-0-2026-118599)

Vulnerability from cvelistv5 – Published: 2026-10-31 09:29 – Updated: 2026-10-31 09:29

Title

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

Summary

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

Severity

5.5 (Medium)


                        
                          CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

CWE

CWE-59 - Improper Link Resolution Before File Access ('Link Following')

Assigner

fedora CNA under the redhat root

CNA scorecard C 69/100 over 42 records in the last 180 days details

References

4 references

URL	Tags
https://access.redhat.com/security/cve/CVE-2026-118599	vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2562969	issue-trackingx_refsource_REDHAT
https://gitlab.gnome.org/GNOME/epiphany/-/work_it…
https://gitlab.gnome.org/GNOME/epiphany/-/merge_r…

Impacted products

1 product

Vendor	Product	Version
GNOME	Epiphany	Affected: 47.0 , < * (semver)

Date Public

2026-10-24 00:00

Credits

Red Hat would like to thank Fernando Munoz for reporting this issue.

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "collectionURL": "https://gitlab.gnome.org/GNOME/epiphany",
          "defaultStatus": "unaffected",
          "packageName": "epiphany",
          "product": "Epiphany",
          "vendor": "GNOME",
          "versions": [
            {
              "lessThan": "*",
              "status": "affected",
              "version": "47.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "Red Hat would like to thank Fernando Munoz for reporting this issue."
        }
      ],
      "datePublic": "2026-10-24T00:00:00.000Z",
      "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\u0027s 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 \u003e= 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"
        }
      ],
      "metrics": [
        {
          "other": {
            "content": {
              "namespace": "https://access.redhat.com/security/updates/classification/",
              "value": "Moderate"
            },
            "type": "Red Hat severity rating"
          }
        },
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "LOCAL",
            "availabilityImpact": "NONE",
            "baseScore": 5.5,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N",
            "version": "3.1"
          },
          "format": "CVSS"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-59",
              "description": "Improper Link Resolution Before File Access (\u0027Link Following\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-31T09:29:37.264Z",
        "orgId": "92fb86c3-55a5-4fb5-9c3f-4757b9e96dc5",
        "shortName": "fedora"
      },
      "references": [
        {
          "tags": [
            "vdb-entry",
            "x_refsource_REDHAT"
          ],
          "url": "https://access.redhat.com/security/cve/CVE-2026-118599"
        },
        {
          "name": "RHBZ#2562969",
          "tags": [
            "issue-tracking",
            "x_refsource_REDHAT"
          ],
          "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2562969"
        },
        {
          "url": "https://gitlab.gnome.org/GNOME/epiphany/-/work_items/2988"
        },
        {
          "url": "https://gitlab.gnome.org/GNOME/epiphany/-/merge_requests/2248"
        }
      ],
      "timeline": [
        {
          "lang": "en",
          "time": "2026-10-23T00:00:00.000Z",
          "value": "Reported to Red Hat."
        },
        {
          "lang": "en",
          "time": "2026-10-24T00:00:00.000Z",
          "value": "Made public."
        }
      ],
      "title": "epiphany: TAR-based .xpi with hard links can overwrite user files during WebExtension install",
      "workarounds": [
        {
          "lang": "en",
          "value": "Do not install WebExtensions (.xpi) from untrusted sources. Prefer keeping WebExtensions disabled when unused (Epiphany can refuse install when the feature is disabled in recent fixes). After any untrusted .xpi install attempt, inspect unexpectedly modified user files (for example shell startup files, autostart desktop entries, or SSH authorized_keys). Upgrade to a fixed Epiphany build containing MR !2248 / commit 0cc9ab55 when available for your stream."
        }
      ],
      "x_generator": {
        "engine": "cvelib 1.8.0"
      },
      "x_redhatCweChain": "CWE-59: Improper Link Resolution Before File Access (\u0027Link Following\u0027)"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "92fb86c3-55a5-4fb5-9c3f-4757b9e96dc5",
    "assignerShortName": "fedora",
    "cveId": "CVE-2026-118599",
    "datePublished": "2026-10-31T09:29:37.264Z",
    "dateReserved": "2026-10-28T16:47:14.805Z",
    "dateUpdated": "2026-10-31T09:29:37.264Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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