Evidence used
- CISA confirms exploitation in the wild.
- The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
- EPSS is 99.97% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2025
CVE-2025-5777High confidence
Citrix NetScaler ADC and Gateway Out-of-Bounds Read Vulnerability
Citrix · NetScaler ADC and Gateway
9.3CriticalCVSS 4.0
Mitigate now
Mitigation availableCISA confirms exploitation in the wild and lists 2025-07-11 as the remediation due date.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityCritical→Operational priority:Critical, unchanged from published severity.unchanged
Compensating controls
- Apply the linked authoritative mitigation while planning the permanent fix.
- 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 Citrix NetScaler ADC and Gateway 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 2025-07-11 as the remediation due date.
Mitigation available01
What, why and how
Citrix NetScaler ADC and Gateway contain an out-of-bounds read vulnerability due to insufficient input validation. This vulnerability can lead to memory overread when the NetScaler is configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server.
What
Citrix NetScaler ADC and Gateway contain an out-of-bounds read vulnerability due to insufficient input validation. This vulnerability can lead to memory overread when the NetScaler is configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server.
Why
The product reads data past the end, or before the beginning, of the intended buffer.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
What
Citrix NetScaler ADC and Gateway contain an out-of-bounds read vulnerability due to insufficient input validation. This vulnerability can lead to memory overread when the NetScaler is configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server.
Why
The product reads data past the end, or before the beginning, of the intended buffer.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. 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 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 2025-07-10. Known ransomware campaign use is recorded.
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 → Out-of-bounds Read → cause the confidentiality, integrity or availability impact described by the vendor
- Attack surface
- Network
- Privileges required
- None: unauthenticated exploitation is possible
- User interaction
- None
- 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-125 ↗
CWE-125: Out-of-bounds Read. The product reads data past the end, or before the beginning, of the intended buffer.
- 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:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:LCommon 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.UINoneUser interaction: No action by another user is required.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
- 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. - Mitigation available
- Action
- Citrix heeft beveiligingsupdates uitgebracht om de kwetsbaarheden te verhelpen. Het NCSC adviseert met klem om deze updates zo snel mogelijk te installeren. Zie de beveiligingsadviezen van Citrix voor meer informatie. **UPDATE 2 van 18 juli 2025. 11.52u:** Aanvullend adviseert het NCSC alle organisaties die NetScaler ADC of NetScaler Gateway gebruiken om technisch onderzoek te doen naar mogelijk misbruik van CVE-2025-5777. Citrix heeft een websitebericht gepubliceerd waarin wordt uitgelegd hoe je je logbestanden op indicaties van misbruik controleert. Tevens heeft Citrix aangegeven op verzoek aanvullende indicators-of-compromise (IOC's) met klanten te delen. Het NCSC adviseert organisaties om deze IOC's bij Citrix op te vragen en systemen op aanwezigheid van deze IOC's te controleren. Daarnaast heeft DoublePulsar een blogpost gepubliceerd met meer context en additionele IOC's. Citrix adviseert daarnaast om alle actieve ICA- en PCoIP-connecties te beëindigen. De blog van DoublePulsar (zie referentie) van 15 juli 2025 benadrukt dat ook RDP-, AAA- en load balancing (LB) persistent sessies beëindigd moeten worden. Het NCSC neemt deze adviezen over, en adviseert organisaties om de genoemde connecties en sessies te beëindigen nadat de beveiligingsupdates zijn geïnstalleerd. Ondanks het installeren van beveiligingsupdates, kunnen Citrix-systemen namelijk nog steeds kwetsbaar zijn doordat sessies die al zijn gestart actief blijven. Een aanvaller die de kwetsbaarheid met kenmerk CVE-2025-5777 heeft misbruikt voordat de beveiligingsupdates zijn geïnstalleerd, kan via deze sessies daardoor toegang tot het systeem behouden. Gebruik de volgende commando's voor het beëindigen van de connecties en sessies: ``` kill icaconnection -all kill pcoipConnection -all kill aaa session -all kill rdp connection -all clear lb persistentSessions ``` Zie de bijgevoegde referenties voor meer informatie.
- 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 17 Jun 2025 · Last source change 4 Aug 2026, 03:55 UTC · CWE-125 · Out-of-bounds Read
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-2025-18497
Product sourceCISA KEV
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
- Vendor guidanceAuthoritative vendor guidance changed: removed remediation: advisories.ncsc.nl/ncsc-2025-0196.json.secure@citrix.com ↗
- Before
- remediation: advisories.ncsc.nl/ncsc-2025-0196.json · vendor advisory: support.citrix.com/article?articleNumber=CTX693420
- After
- vendor advisory: support.citrix.com/article?articleNumber=CTX693420
- Remediation statusRemediation status changed from Mitigation available to Awaiting fix.secure@citrix.com ↗
- Before
- Mitigation available
- After
- Awaiting fix
- Affected versionsThe structured affected or fixed version information changed.CNA ↗
- Before
- 14.1 < 43.56; 13.1 < 58.32 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
- After
- ADC: 14.1 < 43.56, 13.1 < 58.32; Gateway: 14.1 < 43.56, 13.1 < 58.32 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
- Remediation statusRemediation status changed from Awaiting fix to Mitigation available.NCSC-NL ↗
- Before
- Awaiting fix
- After
- Mitigation available
CVE published
Added to CISA KEV
Remediation guidance 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.