Evidence used
- No CISA KEV confirmation is currently recorded.
- EPSS is 16.95% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2009
CVE-2009-4137High confidence
Affected product: Improper Input Validation
Unknown · Unknown
7.5HighCVSS 2.0
Within 7 days
Fix not verifiedHigh technical severity; prioritise exposed affected systems while verifying vendor guidance.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityHigh→Operational priority:High, unchanged from published severity.unchanged
Compensating controls
- Restrict local access and enforce least privilege on affected hosts.
- Monitor vendor guidance and exploitation sources for a material change.
Verification
- Confirm that the asset runs Unknown Unknown and falls inside the recorded affected range.
- Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
- Validate exposure, authentication requirements and compensating controls in the actual environment.
- Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Distribution package intelligence
2 package statesRelease-specific package status
Debian findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.
Repository candidate not checked
A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.
| Distribution release | Source package | Vendor state | Fixed version | Evidence |
|---|---|---|---|---|
| Debian trixietrixie · source | matomo | Not affectedDebian marks this release not affected (fixed-version marker 0). | Not published in this feed | Debian Security Tracker ↗Source updated 22 Oct 2026 |
| Debian sidsid · source | matomo | Not affectedDebian marks this release not affected (fixed-version marker 0). | Not published in this feed | Debian Security Tracker ↗Source updated 22 Oct 2026 |
High technical severity; prioritise exposed affected systems while verifying vendor guidance.
Fix not verified01
What, why and how
The loadContentFromCookie function in core/Cookie.php in Piwik before 0.5 does not validate strings obtained from cookies before calling the unserialize function, which allows remote attackers to execute arbitrary code or upload arbitrary files via vectors related to the __destruct function in the Piwik_Config class; php://filter URIs; the __destruct functions in Zend Framework, as demonstrated by the Zend_Log destructor; the shutdown functions in Zend Framework, as demonstrated by the Zend_Log_Writer_Mail class; the render function in the Piwik_View class; Smarty templates; and the _eval function in Smarty.
What
The loadContentFromCookie function in core/Cookie.php in Piwik before 0.5 does not validate strings obtained from cookies before calling the unserialize function, which allows remote attackers to execute arbitrary code or upload arbitrary files via vectors related to the __destruct function in the Piwik_Config class; php://filter URIs; the __destruct functions in Zend Framework, as demonstrated by the Zend_Log destructor; the shutdown functions in Zend Framework, as demonstrated by the Zend_Log_Writer_Mail class; the render function in the Piwik_View class; Smarty templates; and the _eval function in Smarty.
Why
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
How
An attacker operating through the affected interface may attempt exploitation when the stated preconditions are met. If successful, the issue may execute code or commands in the affected security context.
What
The loadContentFromCookie function in core/Cookie.php in Piwik before 0.5 does not validate strings obtained from cookies before calling the unserialize function, which allows remote attackers to execute arbitrary code or upload arbitrary files via vectors related to the __destruct function in the Piwik_Config class; php://filter URIs; the __destruct functions in Zend Framework, as demonstrated by the Zend_Log destructor; the shutdown functions in Zend Framework, as demonstrated by the Zend_Log_Writer_Mail class; the render function in the Piwik_View class; Smarty templates; and the _eval function in Smarty.
Why
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
How
An attacker operating through the affected interface may attempt exploitation when the stated preconditions are met. If successful, the issue may execute code or commands in the affected security context.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation No confirmed evidence
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
Public PoC / exploit material None recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.
- Likely attack path
- the affected interface → Improper Input Validation → execute code or commands in the affected security context
- Attack surface
- Unspecified
- Privileges required
- None: unauthenticated exploitation is possible
- User interaction
- Not stated in the selected CVSS metric
- Attack complexity
- Low: no specialised conditions are recorded
- Security boundary
- Not stated in the selected CVSS metric
- Weakness
?
CWE means Common Weakness Enumeration: a standard category for the underlying weakness. - CWE-20 ↗
CWE-20: Improper Input Validation. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
- CVSS vector
?
CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity. AV:N/AC:L/Au:N/C:P/I:P/A:P- Post-exploitation / living off the land
- After compromise, an attacker may use built-in shells, scripting engines, scheduled tasks and native network utilities for discovery, persistence or movement. This is a plausible LoTL path, not evidence that it has occurred for every attack.
03
Patch and workaround
Operational remediation based on structured source evidence.
- Status
?
Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change. - Fix not verified
- Affected
- n/a
- Fixed
- No fixed version is explicitly recorded in the structured CVE data.
- Action
- No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
- Workaround
- No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04
Evidence and provenance
Published 24 Dec 2009 · Last source change 16 Sept 2024, 20:27 UTC · CWE-20 · Improper Input Validation
CVE recordCVE.org · 5.1
CVSS sourceNIST NVD
EPSS source FIRST · tracked since 2026-09-13
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2009-4107
Product sourceUnavailable
Remediation sourceCVE/CNA references
CWE sourceNIST NVD
NVD statusNVD modified after enrichment
Missing structured fields: affected product. Missing data is not evidence of low risk; review the primary advisory.
Material change intelligence
View recent updates ↗What changed after publication
- ENISA EUVD mappingEUVD-2009-4107 was added to the official ENISA EUVD mapping for this CVE.ENISA EUVD ↗
- Before
- not recorded
- After
- {"euvdId":"EUVD-2009-4107"}
- Vendor guidanceAuthoritative vendor guidance changed: added vendor advisory: dev.piwik.org/1637; added vendor advisory: piwik.org/piwik-response-to-shocking-news-in-php-exploitation.piwik.org ↗
- Before
- no authoritative guidance recorded
- After
- vendor advisory: dev.piwik.org/1637 · vendor advisory: piwik.org/piwik-response-to-shocking-news-in-php-exploitation
- SeveritySeverity changed from Unknown to High.NIST NVD ↗
- Before
- Unknown
- After
- High
- CVSS scoreCVSS score changed from not recorded to 7.5 (CVSS 2.0 · NIST NVD · AV:N/AC:L/Au:N/C:P/I:P/A:P).NIST NVD ↗
- Before
- not recorded
- After
- 7.5 (CVSS 2.0 · NIST NVD · AV:N/AC:L/Au:N/C:P/I:P/A:P)
- Catalogue recordCVE added to the BlackTree catalogue.CNA ↗
Technical terms and abbreviations used in this report
- CVE
- Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
- CVSS
- Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
- EPSS
- Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
- CWE
- Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
- CNA
- CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
- CISA ADP
- Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
- NVD
- National Vulnerability Database: NIST's enrichment service for CVE records.
- CERT / CSIRT
- A computer security incident response team that publishes warnings or coordinates incident response.
- PoC
- Proof of concept: public material that demonstrates or helps reproduce exploitation.
- CSAF
- Common Security Advisory Framework: a machine-readable format for security advisories.
- LoTL
- Living off the land: abuse of legitimate tools or system functions during an attack.