CVE-2026-53607
ApostropheCMS is an open-source Node.js content management system. In versions up to and including 4.30.0, when `prettyUrls: true` is enabled on `@apostrophecms/file` (a documented SEO feature for serving uploaded files at clean URLs), the public pretty-URL handler builds the upstream URL using the raw `Host` HTTP request header. That URL is then `fetch`'ed and the response body + headers are streamed straight back to the requester.
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Because `Host` is fully attacker-controlled, an unauthenticated remote attacker can pivot the apostrophe process to issue outbound HTTP requests against any host it can reach on the private network. The path component is constrained to `/uploads/attachments/<cuid>-<slug>.<ext>` (built from a local-DB lookup), which keeps the impact narrow: cross-instance data exfiltration is neutralized by cuid uniqueness, but blind-SSRF residuals remain (network-topology mapping via response-code / timing differences and verbose proxy/WAF 404 body disclosure). As of time of publication, no known patched versions exist.
CVSS
- Version: 3.1
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
- Base score: 3.7
Exploitation probability (EPSS)
- Probability of exploitation in the next 30 days: 0.32%
- Percentile among all scored CVEs: 23
- Score date: 10/3/2026
EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).
Affected technologies (2)
⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.
CWEs
- CWE-918
References
Raw JSON (NVD)
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{
"id": "CVE-2026-53607",
"cveTags": [],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-53607",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "poc"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"version": "2.0.3",
"timestamp": "2026-06-15T18:35:31.782532Z"
}
}
],
"cvssMetricV31": [
{
"type": "Secondary",
"source": "security-advisories@github.com",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 3.7,
"attackVector": "NETWORK",
"baseSeverity": "LOW",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N",
"integrityImpact": "NONE",
"userInteraction": "NONE",
"attackComplexity": "HIGH",
"availabilityImpact": "NONE",
"privilegesRequired": "NONE",
"confidentialityImpact": "LOW"
},
"impactScore": 1.4,
"exploitabilityScore": 2.2
}
]
},
"affected": [
{
"source": "security-advisories@github.com",
"affectedData": [
{
"vendor": "apostrophecms",
"product": "apostrophe",
"versions": [
{
"status": "affected",
"version": "<= 4.30.0"
}
]
}
]
}
],
"published": "2026-06-12T21:16:24.247",
"references": [
{
"url": "https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-34pj-2622-jvxq",
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-34pj-2622-jvxq",
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
}
],
"vulnStatus": "Deferred",
"weaknesses": [
{
"type": "Secondary",
"source": "security-advisories@github.com",
"description": [
{
"lang": "en",
"value": "CWE-918"
}
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}
],
"descriptions": [
{
"lang": "en",
"value": "ApostropheCMS is an open-source Node.js content management system. In versions up to and including 4.30.0, when `prettyUrls: true` is enabled on `@apostrophecms/file` (a documented SEO feature for serving uploaded files at clean URLs), the public pretty-URL handler builds the upstream URL using the raw `Host` HTTP request header. That URL is then `fetch`'ed and the response body + headers are streamed straight back to the requester. Because `Host` is fully attacker-controlled, an unauthenticated remote attacker can pivot the apostrophe process to issue outbound HTTP requests against any host it can reach on the private network. The path component is constrained to `/uploads/attachments/<cuid>-<slug>.<ext>` (built from a local-DB lookup), which keeps the impact narrow: cross-instance data exfiltration is neutralized by cuid uniqueness, but blind-SSRF residuals remain (network-topology mapping via response-code / timing differences and verbose proxy/WAF 404 body disclosure). As of time of publication, no known patched versions exist."
}
],
"lastModified": "2026-06-17T10:57:58.183",
"sourceIdentifier": "security-advisories@github.com"
}