CVE-2025-5777

CVE-2025-5777 is a high-severity vulnerability in Citrix Netscaler Application Delivery Controller with a CVSS 3.x base score of 7.5. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2025-07-10). The underlying weakness is classified as CWE-908.

Key facts

• Severity: High (CVSS 3.x base score 7.5)
• CVSS v4: 9.3
• EPSS exploit prediction: 100% (100th percentile)
• Actively exploited: Yes — listed in CISA KEV (added 2025-07-10)
• EU (EUVD) id: EUVD-2025-18497
• EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2025-07-10)
• Weakness: CWE-908
• Affected product: Citrix Netscaler Application Delivery Controller
• Published: 2025-06-17
• Last modified: 2026-08-04

Description

Insufficient input validation leading to memory overread when the NetScaler is configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server

Frequently asked questions

What is CVE-2025-5777?

Insufficient input validation leading to memory overread when the NetScaler is configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server

How severe is CVE-2025-5777?

CVE-2025-5777 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2025-5777 being actively exploited?

Yes. CVE-2025-5777 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2025-07-10, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2025-5777?

CVE-2025-5777 primarily affects Citrix Netscaler Application Delivery Controller. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2025-5777?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2025-5777 have an EU (EUVD) identifier?

Yes. CVE-2025-5777 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-18497. It is also flagged as exploited in the EUVD (since 2025-07-10).

When was CVE-2025-5777 published?

CVE-2025-5777 was published on 2025-06-17 and last updated on 2026-08-04.

References

• https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX693420
• https://citrixbleed.com
• https://horizon3.ai/attack-research/attack-blogs/cve-2025-5777-citrixbleed-2-write-up-maybe/
• https://labs.watchtowr.com/how-much-more-must-we-bleed-citrix-netscaler-memory-disclosure-citrixbleed-2-cve-2025-5777/
• https://www.bleepingcomputer.com/news/security/cisa-tags-citrix-bleed-2-as-exploited-gives-agencies-a-day-to-patch/
• https://www.netscaler.com/blog/news/netscaler-critical-security-updates-for-cve-2025-6543-and-cve-2025-5777/
• https://www.theregister.com/2025/07/10/cisa_citrixbleed_kev/
• https://doublepulsar.com/citrixbleed-2-exploitation-started-mid-june-how-to-spot-it-f3106392aa71
• https://reliaquest.com/blog/threat-spotlight-citrix-bleed-2-vulnerability-in-netscaler-adc-gateway-devices/
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-5777

Affected products (4)

• cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:fips:*:*:*
• cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:ndcpp:*:*:*
• cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:-:*:*:*
• cpe:2.3:a:citrix:netscaler_gateway:*:*:*:*:*:*:*:*

More vulnerabilities in Citrix Netscaler Application Delivery Controller

• CVE-2014-2882 — Critical (CVSS 10.0): Unspecified vulnerability in the management GUI in Citrix NetScaler Application Delivery Controller (ADC) and NetScaler…
• CVE-2014-2881 — Critical (CVSS 10.0): Unspecified vulnerability in the Diffie-Hellman key agreement implementation in the management GUI Java applet in…
• CVE-2026-8655 — Critical (CVSS 9.8): Multiple Memory overflow vulnerabilities in NetScaler ADC and NetScaler Gateway leading to unpredictable or erroneous…
• CVE-2026-8452 — Critical (CVSS 9.8): Memory overflow vulnerability NetScaler ADC and NetScaler Gateway leading to unpredictable or erroneous behavior and…
• CVE-2026-3055 — Critical (CVSS 9.8): Insufficient input validation in NetScaler ADC and NetScaler Gateway when configured as a SAML IDP leading…
• CVE-2025-7776 — Critical (CVSS 9.8): Memory overflow vulnerability leading to unpredictable or erroneous behavior and Denial of Service in NetScaler ADC…

All CVEs affecting Citrix Netscaler Application Delivery Controller →

Other CWE-908 (Use of Uninitialized Resource) vulnerabilities

• CVE-2025-38429 — Critical (CVSS 10.0): In the Linux kernel, the following vulnerability has been resolved: bus: mhi: ep: Update read pointer only after…
• CVE-2026-56190 — Critical (CVSS 9.8): Use of uninitialized resource in Windows RDP allows an unauthorized attacker to execute code over a network.
• CVE-2026-52989 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: nvmet-tcp: propagate nvmet_tcp_build_pdu_iovec()…
• CVE-2022-50335 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: 9p: set req refcount to zero to avoid…
• CVE-2025-38737 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: cifs: Fix oops due to uninitialised variable Fix…
• CVE-2025-38472 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack: fix crash due to removal…

Browse all CWE-908 (Use of Uninitialized Resource) vulnerabilities →