Vulnerability-Lookup

CVE-2026-55877 (GCVE-0-2026-55877)

Vulnerability from cvelistv5 – Published: 2026-07-08 21:32 – Updated: 2026-07-09 14:40

Title

Symfony UX: XSS in symfony/ux-icons via unsanitized SVG content in local files and Iconify on-demand responses

Summary

Symfony UX is a JavaScript ecosystem for Symfony. From 2.17.0 before 2.36.1 and from 3.0.0 before 3.2.0, the ux_icon() Twig function is marked is_safe=['html'] and Icon::toHtml() inlines SVG source verbatim, allowing unsanitized local SVG files or Iconify on-demand JSON body responses containing nested script elements, on* event handlers, or dangerous URL schemes to execute cross-site scripting. This issue is fixed in versions 2.36.1 and 3.2.0.

Severity

6.1 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-09 14:21 UTC

CWE

CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Assigner

GitHub_M CNA under the mitre root

CNA scorecard C 72/100 over 7886 records in the last 180 days details

References

4 references

URL	Tags
https://github.com/symfony/ux/security/advisories…	x_refsource_CONFIRM
https://github.com/symfony/ux/commit/3a4964ec3700…	x_refsource_MISC
https://github.com/symfony/ux/releases/tag/v2.36.1	x_refsource_MISC
https://github.com/symfony/ux/releases/tag/v3.2.0	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
symfony	ux	Affected: >= 2.17.0, < 2.36.1 Affected: >= 3.0.0, < 3.2.0	guessed

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-55877

Vulnerability from fkie_nvd - Published: 2026-07-08 22:17 - Updated: 2026-10-25 17:10

Severity

6.1 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Summary

References

URL	Tags
security-advisories@github.com	https://github.com/symfony/ux/commit/3a4964ec3700f0af4e13f7bfbf8bb3174c3e79d1	Patch
security-advisories@github.com	https://github.com/symfony/ux/releases/tag/v2.36.1	Release Notes
security-advisories@github.com	https://github.com/symfony/ux/releases/tag/v3.2.0	Release Notes
security-advisories@github.com	https://github.com/symfony/ux/security/advisories/GHSA-6v8j-33hc-mv84	Vendor Advisory

Impacted products

	Vendor	Product	Version
	symfony	ux	*
	symfony	ux	*

JSON

To clipboard

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  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-79"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}

GHSA-6V8J-33HC-MV84

Vulnerability from github – Published: 2026-06-19 21:42 – Updated: 2026-06-19 21:42

Summary

symfony/ux-icons: XSS via unsanitized SVG content in local files and Iconify on-demand responses

Details

Description

The ux_icon() Twig function is marked is_safe=['html'], so Twig never escapes its output. Icon::toHtml() inlines the SVG source verbatim into the page. Browsers execute <script> elements and on* event-handler attributes found inside inline SVG, making any unsanitized icon a vector for cross-site scripting.

Two code paths were affected. In the local file path, Icon::fromFile() only stripped <script> elements that were direct children of <svg>, leaving nested scripts and all on* attributes untouched despite a code comment claiming broader protection. In the Iconify on-demand path (enabled by default), the remote JSON body field was wrapped into an Icon object with no sanitization at all. Concrete attack vectors include a malicious SVG icon pack from a third-party theme or downloaded icon set, or a controlled Iconify endpoint configured via iconify.endpoint (including a poisoned cache).

Resolution

Introducing an IconFactory that centralizes sanitization across every icon source before an Icon object is created. The sanitizer removes script-capable elements (script, foreignObject, iframe, object, embed), SMIL animations targeting on*, href, or xlink:href attributes, CDATA sections, processing instructions, all on* attributes, and javascript:, vbscript:, and data:text/html URL schemes. <style> elements are kept for theming but have any handlers stripped. Icons that contain none of these constructs are byte-for-byte identical after sanitization.

Credits

Symfony would like to thank Pascal Cescon for reporting the issue and Hugo Alliaume for providing the fix.

Severity

6.1 (Medium)


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

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "symfony/ux-icons"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.17.0"
            },
            {
              "fixed": "2.36.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "symfony/ux-icons"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.0.0"
            },
            {
              "fixed": "3.2.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-55877"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-19T21:42:15Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Description\n\nThe `ux_icon()` Twig function is marked `is_safe=[\u0027html\u0027]`, so Twig never escapes its output. `Icon::toHtml()` inlines the SVG source verbatim into the page. Browsers execute `\u003cscript\u003e` elements and `on*` event-handler attributes found inside inline SVG, making any unsanitized icon a vector for cross-site scripting.\n\nTwo code paths were affected. In the local file path, `Icon::fromFile()` only stripped `\u003cscript\u003e` elements that were direct children of `\u003csvg\u003e`, leaving nested scripts and all `on*` attributes untouched despite a code comment claiming broader protection. In the Iconify on-demand path (enabled by default), the remote JSON `body` field was wrapped into an `Icon` object with no sanitization at all. Concrete attack vectors include a malicious SVG icon pack from a third-party theme or downloaded icon set, or a controlled Iconify endpoint configured via `iconify.endpoint` (including a poisoned cache).\n\n### Resolution\n\nIntroducing an `IconFactory` that centralizes sanitization across every icon source before an `Icon` object is created. The sanitizer removes script-capable elements (`script`, `foreignObject`, `iframe`, `object`, `embed`), SMIL animations targeting `on*`, `href`, or `xlink:href` attributes, CDATA sections, processing instructions, all `on*` attributes, and `javascript:`, `vbscript:`, and `data:text/html` URL schemes. \n`\u003cstyle\u003e` elements are kept for theming but have any handlers stripped. Icons that contain none of these constructs are byte-for-byte identical after sanitization. \n\n### Credits\n\nSymfony would like to thank Pascal Cescon for reporting the issue and Hugo Alliaume for providing the fix.",
  "id": "GHSA-6v8j-33hc-mv84",
  "modified": "2026-06-19T21:42:15Z",
  "published": "2026-06-19T21:42:15Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/symfony/ux/security/advisories/GHSA-6v8j-33hc-mv84"
    },
    {
      "type": "WEB",
      "url": "https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/ux-icons/CVE-2026-55877.yaml"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/symfony/ux"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "symfony/ux-icons: XSS via unsanitized SVG content in local files and Iconify on-demand responses"
}

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.

Vulnerability timeline

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Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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CVE-2026-55877 (GCVE-0-2026-55877)

FKIE_CVE-2026-55877

GHSA-6V8J-33HC-MV84

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