What it is
CVE-2025-35939 is an unauthenticated Craft CMS stores user-provided content in session files.
Vulnerability report
Exploited in the wild
Confirmed confidence
In CISA KEV
CVE-2025-35939
Craft CMS stores user-provided content in session files
Craft / CMS · affected before 5.7.5
- Severity
- CVSS 6.9 · Medium
- Confidence
- Confirmed
- Exploit status
- Exploited in the wild
- EPSS
- 1.3%
- First observed
- —
- Last observed
- —
Decision summary
What security teams need to know first
Direct answers before the deeper technical record.
Is it exploited?
Yes. KEV Intelligence tracks this CVE as a known exploited vulnerability. Confidence is confirmed.
Who is affected?
Craft / CMS affected before 5.7.5.
What should we do?
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
Overview
Craft CMS stores arbitrary content provided by unauthenticated users in session files
Craft CMS stores arbitrary content provided by unauthenticated users in session files. This content could be accessed and executed, possibly using an independent vulnerability. Craft CMS redirects requests that require authentication to the login page and generates a session file on the server at '/var/lib/php/sessions'. Such session files are named 'sess_[session_value]', where '[session_value]' is provided to the client in a 'Set-Cookie' response header.
Craft CMS stores the return URL requested by the client without sanitizing parameters. Consequently, an unauthenticated client can introduce arbitrary values, such as PHP code, to a known local file location on the server. Craft CMS versions 5.7.5 and 4.15.3 have been released to address this issue.
Vendor
Product
Affected
Status
Craft
CMS
Before 5.7.5
Affected
Craft
CMS
5.7.5
Unaffected
Craft
CMS
Before 4.15.3
Affected
Craft
CMS
4.15.3
Unaffected
- Published
- 07 May 2025
- Exploitation Reported
- 01 Jun 2026
- Attack vector
- Remote
- Complexity
- Low
- Privileges
- None
- User interaction
- None
Tags
php
cisa
CVE References
- CVE Record CVE.org · CVE Record https://www.cve.org/CVERecord?id=CVE-2025-35939
- url github.com · CVE Record https://github.com/craftcms/cms/pull/17220
- url github.com · CVE Record https://github.com/craftcms/cms/releases/tag/4.15.3
- url github.com · CVE Record https://github.com/craftcms/cms/releases/tag/5.7.5
- url raw.githubusercontent.com · CVE Record https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/...
Exploitation evidence
Why KEV Intelligence marks this CVE as exploited
Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.
Exploited in the wild
CVE
Independent exploitation attestation added to the KEV Intelligence record.
Known exploited vulnerability sources
Per-source evidence links for KEV attestations are available through the KEV Intelligence Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| CVE First | 2026-06-01 10:31 UTC |
| CISA | 2026-06-02 14:07 UTC |
Detection
Operational artifacts and observed signals
Make the evidence actionable in scanner, SOC, and edge-control workflows.
Observed signals
- Request targets
- 0
- User-Agents
- 0
Raw values available in Pro and Enterprise.
Scanner coverage
No scanner integrations recorded yet.
Virtual patch status
No KEV Intelligence virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.
Learn about virtual patches →No detection artifacts or sensor request patterns are available for this CVE yet.
Check back as sensor telemetry and scanner integrations are updated.
Risk and context
Severity, weaknesses, and research context
CVSS v4.0
6.9
Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
EPSS
1.3%
All CVSS Scores
CVSS v4.0
6.9
Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
CVSS v3.1
5.3
Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Timeline
From disclosure to observed exploitation
-
Added to CISA KEV
Listed in the CISA Known Exploited Vulnerabilities catalog
-
Added to KEV Intelligence KEV Feed
High-confidence, third-party attested exploitation
-
CVE published
Vulnerability disclosed publicly
-
CVE ID reserved
Identifier reserved by the CNA
Pro API
Automate this intelligence
Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
- Evidence confidence and provenance
- First-party sensor telemetry
- PoC and scanner references
- Affected versions and enrichment
- Automation-ready JSON delivery
GET /api/v2/pro/kevs/CVE-2025-35939
Free JSON includes basic KEV fields{
"cve_id": "CVE-2025-35939",
"confidence": "Confirmed",
"cvss_score": 6.9,
"cvss_estimated": false,
"epss_score": 0.01317,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "attempts": 0, "sensors": 0 }
}Early warning alerts
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