Threats / Citrix / CVE-2026-3055
CVE-2026-3055
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-09-19
Citrix NetScaler vulnerability
Citrix NetScaler contains an out-of-bounds read vulnerability in SAML IDP configuration, enabling memory disclosure through crafted requests.
Verdict
Today item — known-exploited.
An out-of-bounds read in NetScaler SAML IDP processing allows unauthenticated attackers to leak sensitive memory contents. The high EPSS score and active exploitation reflect the ease of triggering memory disclosure on internet-facing deployments.
CISA KEV Yes · 2026-03-305EPSS 0.87166 (verify live)6CVSS 9.33CISA SSVC Exploitation: active · Automatable: yes · Impact: total4Exploit Public PoC / detection · Metasploit module · nuclei template13
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
196 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-03-30).
Probability (EPSS)
EPSS 0.87166 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 9.3 (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L) · Affected: Citrix, NetScaler. Confirm exact fixed builds in the vendor advisory.CVSS — CNA-assigned (CVE.org), version 4.0, set at disclosure.
Weakness (CWE)
Mapped to CWE-125 Out-of-bounds Read — weakness family: Memory safety.CWE — CNA-assigned (CVE.org); the weakness class drives how the flaw is exploited.
CISA SSVC (triage disposition)
Exploitation: active · Automatable: yes · Technical Impact: totalCISA's own stakeholder-specific triage inputs, published in the CVE record (CISA Coordinator role). NOTE: this is CISA's three decision points; the final Act/Attend/Track decision also requires a Mission & Well-being input not published here, so no overall decision is asserted.
Currency of the record
CISA added this to its KEV catalog 7 days after the CVE record was published.KEV lag = CISA-KEV dateAdded − CVE.org datePublished; a floor on how long the known-exploited flaw sat in the public record before the federal catalog listed it. Severity/weakness here is CNA- or CISA-assigned (current at disclosure), independent of NVD's analysis backlog.
Public exploit available
Public exploit tooling is catalogued for this CVE (a public proof-of-concept / detection template). Catalog entries: Metasploit module, nuclei template. We link the catalog page(s) only — no payload or code is hosted or restated here.Link, never host — the catalog page is the source; basicsecurity.net does not redistribute payloads.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I craft a malformed SAML request to trigger an out-of-bounds read in the IDP parser.
Business
Sensitive data in server memory, including credentials and session tokens, becomes accessible to attackers without authentication.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I extract leaked memory contents to identify authentication secrets or encryption keys.
Business
Compromised credentials enable lateral movement and unauthorized access to protected resources and downstream systems.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05
Coverage & confidence
— what we know, and what we don’tEstablished (cited)
Coverage gaps — stated, not hidden
Disclosure & credit2
Catalogued by NetScalerCNA
Credited with finding itNo finder is named in the public CVE record or the scanned vendor advisory — attribution scoped to the sources checked.
Found an error? Propose a correction.
A correction is a cited counter-claim — it must cite a source,
gets reviewed by a second human, and is never auto-applied. See the
correction convention and our identity
npub1j7gt9ky7sfcrjn8jjee6693dkzvk4rahs0fk2suu7968dfns62zs3mqm3y.