Evidence used
- CISA confirms exploitation in the wild.
- EPSS is 1.40% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2026
CVE-2026-102489High confidence
Zammad GmbH Zammad Session Fixation Vulnerability
Zammad GmbH · Zammad
8.7HighCVSS 4.0
Protect now
Fix not verifiedCISA confirms exploitation in the wild and lists 2026-10-05 as the remediation due date.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityHigh→Operational priority:Critical, raised one band.upgradedsince 2 Oct 2026
Compensating controls
- 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 Zammad GmbH Zammad 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.
CISA confirms exploitation in the wild and lists 2026-10-05 as the remediation due date.
Fix not verified01
What, why and how
Zammad GmbH Zammad contains a session fixation vulnerability that can lead to remote code execution as the zammad user. This vulnerability can be chained with CVE-2026-102490.
What
Zammad GmbH Zammad contains a session fixation vulnerability that can lead to remote code execution as the zammad user. This vulnerability can be chained with CVE-2026-102490.
Why
Authenticating a user, or otherwise establishing a new user session, without invalidating any existing session identifier gives an attacker the opportunity to steal authenticated sessions.
How
An attacker operating through a network path may attempt exploitation when the stated preconditions are met. If successful, the issue may execute code or commands in the affected security context.
What
Zammad GmbH Zammad contains a session fixation vulnerability that can lead to remote code execution as the zammad user. This vulnerability can be chained with CVE-2026-102490.
Why
Authenticating a user, or otherwise establishing a new user session, without invalidating any existing session identifier gives an attacker the opportunity to steal authenticated sessions.
How
An attacker operating through a network path 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 Confirmed in the wild
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.CISA added this CVE to its Known Exploited Vulnerabilities catalogue on 2026-10-02.
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
- a network path → Session Fixation → execute code or commands in the affected security context
- Attack surface
- Network
- Privileges required
- None: unauthenticated exploitation is possible
- User interaction
- Passive interaction required
- Attack complexity
- Low: no specialised conditions are recorded
- Security boundary
- Not a CVSS 4.0 base metric
- Weakness
?
CWE means Common Weakness Enumeration: a standard category for the underlying weakness. - CWE-384 ↗
CWE-384: Session Fixation. Authenticating a user, or otherwise establishing a new user session, without invalidating any existing session identifier gives an attacker the opportunity to steal authenticated sessions.
- CVSS vector
?
CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity. CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L/E:A/AU:Y/V:CCommon Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.ATNoneAttack requirements: No additional deployment or execution condition is required.PRNonePrivileges required: The attacker does not need an account or existing privileges.UIPassiveUser interaction: A user must unknowingly interact with the vulnerable system.VCHighVulnerable-system confidentiality: A successful attack can cause a major loss.VIHighVulnerable-system integrity: A successful attack can cause a major loss.VAHighVulnerable-system availability: A successful attack can cause a major loss.SCLowSubsequent-system confidentiality: A successful attack can cause a limited loss.SILowSubsequent-system integrity: A successful attack can cause a limited loss.SALowSubsequent-system availability: A successful attack can cause a limited loss.- 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
- Zammad: * < 6.3.0, 6.3.0 < 6.5.4, 7.0.0 < 7.1.3
- 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. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04
Evidence and provenance
Published 30 Sept 2026 · Last source change 7 Oct 2026, 14:03 UTC · CWE-384 · Session Fixation
CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source FIRST · tracked since 2026-10-01
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2026-90080
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCISA ADP
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
- Vendor guidanceAuthoritative vendor guidance changed: added vendor advisory: community.zammad.org/2; added vendor advisory: zammad.com/cve-2026-102489-cve-2026-102490.csirt@divd.nl ↗
- Before
- no authoritative guidance recorded
- After
- vendor advisory: community.zammad.org/2 · vendor advisory: zammad.com/cve-2026-102489-cve-2026-102490
- Vendor guidanceAuthoritative vendor guidance changed: removed vendor advisory: zammad.com/cve-2026-102489-cve-2026-102490.CNA ↗
- Before
- vendor advisory: zammad.com/cve-2026-102489-cve-2026-102490
- After
- no authoritative guidance recorded
- Vendor guidanceAuthoritative vendor guidance changed: added vendor advisory: zammad.com/cve-2026-102489-cve-2026-102490; removed remediation: csirt.divd.nl/DIVD-2026-00015.zammad.com ↗
- Before
- remediation: csirt.divd.nl/DIVD-2026-00015
- After
- vendor advisory: zammad.com/cve-2026-102489-cve-2026-102490
- Affected versionsThe structured affected or fixed version information changed.CNA ↗
- Before
- Zammad: * < 6.3.0, 6.3.0 < 6.5.4 · Fixed: Zammad: 7.0.0 < *
- After
- Zammad: * < 6.3.0, 6.3.0 < 6.5.4, 7.0.0 < 7.1.3 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
- Remediation statusRemediation status changed from Patch available to Awaiting fix.zammad.com ↗
- Before
- Patch available
- After
- Awaiting fix
- CISA KEV stateCISA KEV now confirms exploitation in the wild.CISA KEV ↗
- Before
- not listed in CISA KEV
- After
- listed in CISA KEV since 2026-10-02
- ENISA known-exploited stateENISA EUVD now records this CVE in its known-exploited dataset.ENISA EUVD ↗
- Before
- not listed in ENISA EUVD known-exploited dataset
- After
- listed in ENISA EUVD known-exploited dataset (EUVD-2026-90080)
- BlackTree coverageBlackTree article coverage changed from no BlackTree article to 1 BlackTree article.BlackTree editorial ↗
- Before
- no BlackTree article
- After
- 1 BlackTree article
- ENISA EUVD mappingEUVD-2026-90080 was added to the official ENISA EUVD mapping for this CVE.ENISA EUVD ↗
- Before
- not recorded
- After
- {"euvdId":"EUVD-2026-90080"}
- 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.