GHSA-3QX2-6F78-W2J2
Vulnerability from github – Published: 2023-12-13 23:09 – Updated: 2023-12-13 23:09Summary
When parsing SVG images Dompdf performs an initial validation to ensure that paths within the SVG are allowed. One of the validations is that the SVG document does not reference itself. However, a recursive chained using two or more SVG documents is not correctly validated. Depending on the system configuration and attack pattern this could exhaust the memory available to the executing process and/or to the server itself.
Details
php-svg-lib, when run in isolation, does not support SVG references for image elements. An SVG document can, however, be referenced and Dompdf will run that reference through the same validation. Dompdf currently includes validation to prevent self-referential image references, but a chained reference is not checked. A malicious actor may thus trigger infinite recursion in the validation process by chaining references between two or more SVG images.
PoC
This following sources can be used to bypass validation provided by Dompdf:
recurse.html
<img src="one.svg">
one.svg
<svg width="200" height="200" xmlns="http://www.w3.org/2000/svg">
<image href="two.svg" />
</svg>
two.svg
<svg width="200" height="200" xmlns="http://www.w3.org/2000/svg">
<image href="one.svg" />
</svg>
Impact
When Dompdf parses the above payload, it will crash due after exceeding the allowed execution time or memory usage. An attacker sending multiple request to a system can potentially cause resource exhaustion to the point that the system is unable to handle incoming request.
{
"affected": [
{
"package": {
"ecosystem": "Packagist",
"name": "dompdf/dompdf"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "2.0.4"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2023-50262"
],
"database_specific": {
"cwe_ids": [
"CWE-20"
],
"github_reviewed": true,
"github_reviewed_at": "2023-12-13T23:09:04Z",
"nvd_published_at": "2023-12-13T21:15:09Z",
"severity": "MODERATE"
},
"details": "### Summary\nWhen parsing SVG images Dompdf performs an initial validation to ensure that paths within the SVG are allowed. One of the validations is that the [SVG document does not reference itself](https://github.com/dompdf/dompdf/blob/v2.0.3/src/Image/Cache.php#L136-L153). However, a recursive chained using two or more SVG documents is not correctly validated. Depending on the system configuration and attack pattern this could exhaust the memory available to the executing process and/or to the server itself.\n\n### Details\nphp-svg-lib, when run in isolation, does not support SVG references for `image` elements. An SVG document can, however, be referenced and Dompdf will run that reference through the same validation. Dompdf currently includes validation to prevent self-referential `image` references, but a chained reference is not checked. A malicious actor may thus trigger infinite recursion in the validation process by chaining references between two or more SVG images.\n\n### PoC\n\nThis following sources can be used to bypass validation provided by Dompdf:\n\nrecurse.html\n```\n\u003cimg src=\"one.svg\"\u003e\n```\n\none.svg\n```\n\u003csvg width=\"200\" height=\"200\" xmlns=\"http://www.w3.org/2000/svg\"\u003e\n \u003cimage href=\"two.svg\" /\u003e\n\u003c/svg\u003e\n```\n\ntwo.svg\n```\n\u003csvg width=\"200\" height=\"200\" xmlns=\"http://www.w3.org/2000/svg\"\u003e\n \u003cimage href=\"one.svg\" /\u003e\n\u003c/svg\u003e\n```\n\n### Impact\n\nWhen Dompdf parses the above payload, it will crash due after exceeding the allowed execution time or memory usage. An attacker sending multiple request to a system can potentially cause resource exhaustion to the point that the system is unable to handle incoming request.",
"id": "GHSA-3qx2-6f78-w2j2",
"modified": "2023-12-13T23:09:04Z",
"published": "2023-12-13T23:09:04Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/dompdf/dompdf/security/advisories/GHSA-3qx2-6f78-w2j2"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-50262"
},
{
"type": "WEB",
"url": "https://github.com/dompdf/dompdf/commit/41cbac16f3cf56affa49f06e8dae66d0eac2b593"
},
{
"type": "WEB",
"url": "https://github.com/FriendsOfPHP/security-advisories/blob/master/dompdf/dompdf/CVE-2023-50262.yaml"
},
{
"type": "PACKAGE",
"url": "https://github.com/dompdf/dompdf"
},
{
"type": "WEB",
"url": "https://github.com/dompdf/dompdf/blob/v2.0.3/src/Image/Cache.php#L136-L153"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
"type": "CVSS_V3"
}
],
"summary": "Denial of service caused by infinite recursion when parsing SVG images"
}
Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.
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
Sightings and recorded dates, grouped by day · UTC
How durations are calculated
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.
Loading timeline…
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.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.