Evidence used
- No CISA KEV confirmation is currently recorded.
- A structured source references public exploit or proof-of-concept material.
- EPSS is 0.36% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2026
CVE-2026-24891High confidence
openITCOCKPIT has Unsafe PHP Deserialization in Gearman Worker Allowing Conditional Object Injection
openITCOCKPIT · openITCOCKPIT
Official source article: GitHub GHSA-X4MQ-8GFG-FRC4 ↗. Check the applicable product and release in the original source.
7.5HighCVSS 3.1
Within 7 days
Patch availableHigh technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityHigh→Operational priority:Critical, raised one band.upgradedsince 20 Feb 2026
Compensating controls
- Validate the affected product branch and deploy the verified fixed release.
- Restrict the affected network interface to trusted sources where business-safe.
- Increase monitoring for the attack path and post-exploitation behaviour described in the report.
Verification
- Confirm that the asset runs openITCOCKPIT openITCOCKPIT and falls inside the recorded affected range.
- Verify the installed build against the product-specific fixed version after deployment.
- Validate exposure, authentication requirements and compensating controls in the actual environment.
- Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
High technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.
Patch available01
What, why and how
openITCOCKPIT is an open source monitoring tool built for different monitoring engines like Nagios, Naemon and Prometheus. Versions 5.3.1 and below contain an unsafe deserialization sink in the Gearman worker implementation. The worker function registered as oitc_gearman calls PHP's unserialize() on job payloads without enforcing class restrictions or validating data origin. While the intended deployment assumes only trusted internal components enqueue Gearman jobs, this trust boundary is not enforced in application code. In environments where the Gearman service or worker is exposed to untrusted systems, an attacker may submit crafted serialized payloads to trigger PHP Object Injection in the worker process. This vulnerability is exploitable when Gearman listens on non-local interfaces, network access to TCP/4730 is unrestricted, or untrusted systems can enqueue jobs. Default, correctly hardened deployments may not be immediately exploitable, but the unsafe sink remains present in code regardless of deployment configuration. Enforcing this trust boundary in code would significantly reduce risk and prevent exploitation in misconfigured environments. This issue has been fixed in version 5.4.0.
What
openITCOCKPIT is an open source monitoring tool built for different monitoring engines like Nagios, Naemon and Prometheus. Versions 5.3.1 and below contain an unsafe deserialization sink in the Gearman worker implementation. The worker function registered as oitc_gearman calls PHP's unserialize() on job payloads without enforcing class restrictions or validating data origin. While the intended deployment assumes only trusted internal components enqueue Gearman jobs, this trust boundary is not enforced in application code. In environments where the Gearman service or worker is exposed to untrusted systems, an attacker may submit crafted serialized payloads to trigger PHP Object Injection in the worker process. This vulnerability is exploitable when Gearman listens on non-local interfaces, network access to TCP/4730 is unrestricted, or untrusted systems can enqueue jobs. Default, correctly hardened deployments may not be immediately exploitable, but the unsafe sink remains present in code regardless of deployment configuration. Enforcing this trust boundary in code would significantly reduce risk and prevent exploitation in misconfigured environments. This issue has been fixed in version 5.4.0.
Why
Attacker-influenced serialised data is reconstructed as trusted objects, which can invoke dangerous application behaviour.
How
An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
What
openITCOCKPIT is an open source monitoring tool built for different monitoring engines like Nagios, Naemon and Prometheus. Versions 5.3.1 and below contain an unsafe deserialization sink in the Gearman worker implementation. The worker function registered as oitc_gearman calls PHP's unserialize() on job payloads without enforcing class restrictions or validating data origin. While the intended deployment assumes only trusted internal components enqueue Gearman jobs, this trust boundary is not enforced in application code. In environments where the Gearman service or worker is exposed to untrusted systems, an attacker may submit crafted serialized payloads to trigger PHP Object Injection in the worker process. This vulnerability is exploitable when Gearman listens on non-local interfaces, network access to TCP/4730 is unrestricted, or untrusted systems can enqueue jobs. Default, correctly hardened deployments may not be immediately exploitable, but the unsafe sink remains present in code regardless of deployment configuration. Enforcing this trust boundary in code would significantly reduce risk and prevent exploitation in misconfigured environments. This issue has been fixed in version 5.4.0.
Why
Attacker-influenced serialised data is reconstructed as trusted objects, which can invoke dangerous application behaviour.
How
An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
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 Reference recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.
- Likely attack path
- a network path → Deserialization of Untrusted Data → cause the confidentiality, integrity or availability impact described by the vendor
- Attack surface
- Network
- Privileges required
- Low: a basic authenticated account is required
- User interaction
- None
- Attack complexity
- High: exploitation depends on specific conditions
- Security boundary
- Unchanged: impact remains within the vulnerable component's security authority
- Weakness
?
CWE means Common Weakness Enumeration: a standard category for the underlying weakness. - CWE-502 ↗
CWE-502: Deserialization of Untrusted Data. The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.
- CVSS vector
?
CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity. CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:HCommon Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.- Post-exploitation / living off the land
- No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
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. - Patch available
- Affected
- openITCOCKPIT: < 5.4.0
- Fixed
- 5.4.0.
- Action
- Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
- Workaround
- No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04
Evidence and provenance
Published 20 Feb 2026 · Last source change 20 Feb 2026, 18:42 UTC · CWE-502 · Deserialization of Untrusted Data
CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source FIRST · tracked since 2026-08-14
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2026-8363
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD enriched
Core structured fields are present and their contributing authorities are shown above.
Material change intelligence
View recent updates ↗What changed after publication
No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.
CVE published
Fixed release or patch reference recorded
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.