plone.app.portlets: Denial of service via RSS feed portlet
plone.app.portlets provides portlets and a Plone-specific user interface for plone.portlets. Prior to 5.0.8, 6.0.4, and 7.0.2, a member who can add an RSS portlet can set its feed URL to a very large response, causing src/plone/app/portlets/portlets/rss.py to download and retain excessive data in memory and deny service. The same RSS URL handling accepts internal hosts, IP addresses, single-word domains, and explicit ports, allowing server-side requests that can probe internal network services and open ports. A malicious feed item can also supply a JavaScript URL that is retained as the item link and can execute script when used by a victim. The affected logic includes _rss_feed_url_validator, _normal_url_validator, RSSFeed._retrieveFeed, RSSFeed._buildItemDict, and the FEED_DATA in-memory cache. This issue is fixed in versions 5.0.8, 6.0.4, and 7.0.2.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-55248
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 4 Nov 2026, 11:07 UTC · Revision 1
Source evidence
plone.app.portlets: Denial of service via RSS feed portlet
core-osv · Original sourcePublished 28 Aug 2026, 18:40 UTC
plone.app.portlets provides portlets and a Plone-specific user interface for plone.portlets. Prior to 5.0.8, 6.0.4, and 7.0.2, a member who can add an RSS portlet can set its feed URL to a very large response, causing src/plone/app/portlets/portlets/rss.py to download and retain excessive data in memory and deny service. The same RSS URL handling accepts internal hosts, IP addresses, single-word domains, and explicit ports, allowing server-side requests that can probe internal network services and open ports. A malicious feed item can also supply a JavaScript URL that is retained as the item link and can execute script when used by a victim. The affected logic includes _rss_feed_url_validator, _normal_url_validator, RSSFeed._retrieveFeed, RSSFeed._buildItemDict, and the FEED_DATA in-memory cache. This issue is fixed in versions 5.0.8, 6.0.4, and 7.0.2.
osv:CVE-2026-55248
Complete source record
{
"id": "bc63d9d1e5f2bcde1282ca27df8b74a14167855e167a69adee86a429761c55c7",
"url": "https://osv.dev/vulnerability/CVE-2026-55248",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "plone.app.portlets: Denial of service via RSS feed portlet",
"summary": "plone.app.portlets provides portlets and a Plone-specific user interface for plone.portlets. Prior to 5.0.8, 6.0.4, and 7.0.2, a member who can add an RSS portlet can set its feed URL to a very large response, causing src/plone/app/portlets/portlets/rss.py to download and retain excessive data in memory and deny service. The same RSS URL handling accepts internal hosts, IP addresses, single-word domains, and explicit ports, allowing server-side requests that can probe internal network services and open ports. A malicious feed item can also supply a JavaScript URL that is retained as the item link and can execute script when used by a victim. The affected logic includes _rss_feed_url_validator, _normal_url_validator, RSSFeed._retrieveFeed, RSSFeed._buildItemDict, and the FEED_DATA in-memory cache. This issue is fixed in versions 5.0.8, 6.0.4, and 7.0.2.",
"evidence": "osv:CVE-2026-55248",
"products": [],
"severity": "critical",
"structured": {
"id": "CVE-2026-55248",
"aliases": [
"CVE-2026-55248",
"GHSA-x5g3-w747-2h8q",
"PYSEC-2026-3884"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/plone/plone.app.portlets",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"fixed": "7276bf16644ef7613d9b7c0166312cf6cd903bc1"
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{
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{
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{
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}
],
"database_specific": {
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"source": "AFFECTED_FIELD",
"strategy": "StringRangeExpression"
},
{
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{
"fixed": "6.0.4"
}
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"source": "AFFECTED_FIELD",
"strategy": "StringRangeExpression"
},
{
"range": [
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{
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"source": "AFFECTED_FIELD",
"strategy": "StringRangeExpression"
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{
"range": [
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"source": "REFERENCES_COMMIT"
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{
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"source": "REFERENCES_COMMIT"
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{
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],
"versions": [
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"2.0a2",
"2.0a1",
"iteration1"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-55248.json"
}
}
],
"modified": "2026-10-28T02:30:34.874491224Z",
"provider": "osv",
"references": [
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55248.json",
"https://github.com/plone/plone.app.portlets/security/advisories/GHSA-x5g3-w747-2h8q",
"https://nvd.nist.gov/vuln/detail/CVE-2026-55248",
"https://github.com/plone/plone.app.portlets/commit/09da52ef7b297daa8e0cfd2361e47c37d9b073ad",
"https://github.com/plone/plone.app.portlets/commit/9f16b6fb10211916686c6c346ea174bf517e3fbd",
"https://github.com/plone/plone.app.portlets/commit/a3b2c2887165b308cd915cbb87b8276f90a76680",
"https://github.com/plone/plone.app.portlets/commit/df5e256baee55083cbd6b9a2623675d4cb26b6cd"
],
"provider_metadata": {
"cwe_ids": [
"CWE-400"
],
"cna_assigner": "GitHub_M",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55248.json"
}
},
"related_cves": [
{
"value": "CVE-2026-55248",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 501944,
"published_at": "2026-08-28T18:40:50.582+00:00"
}