CVE-2026-3055

Published Mar 23, 2026

Last updated 7 months ago

Exploit knownCVSS critical 9.3
VDI
Ubuntu
Network
SSL
Supply chain
Tunneling protocol
Server
OT
Mobile device
Port (80)
Port (443)

Overview

Description
Insufficient input validation in NetScaler ADC and NetScaler Gateway when configured as a SAML IDP leading to memory overread
Source
50a63c94-1ea7-4568-8c11-eb79e7c5a2b5
NVD status
Analyzed
Products
netscaler_application_delivery_controller, netscaler_gateway

Risk scores

CVSS 4.0

Type
Secondary
Base score
9.3
Impact score
-
Exploitability score
-
Vector string
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Severity
CRITICAL

CVSS 3.1

Type
Primary
Base score
9.8
Impact score
5.9
Exploitability score
3.9
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Severity
CRITICAL

Known exploits

Data from CISA

Vulnerability name
Citrix NetScaler Out-of-Bounds Read Vulnerability
Exploit added on
Mar 30, 2026
Exploit action due
Apr 2, 2026
Required action
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Weaknesses

50a63c94-1ea7-4568-8c11-eb79e7c5a2b5
CWE-125

Social media

Hype score
Not currently trending
  1. HUGIN Case Intelligence Case: CVE-2026-3055 / NetScaler ADC and NetScaler Gateway Observed Evidence: - Active exploitation reported - Live exploitation observed by VulnCheck canaries Evidence State: DISCLOSED, ACTIVE_EXPLOITATION Assessment:

    @HuginIntel

    9 Oct 2026

    1 Impression

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  2. 🚨 Edge infrastructure is failing first — again. CISA just added two critical flaws to the KEV catalog: • Citrix NetScaler CVE-2026-3055 (memory overread via SAML IdP) • F5 BIG-IP APM CVE-2025-53521 (unauthenticated RCE) Both are actively exploited. New article → htt

    @ByteVanguardSec

    7 Apr 2026

    113 Impressions

    0 Retweets

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  3. 💡IR/CERT Morning Brief (4/1) 1/ • Priority issues: NetScaler CVE-2026-3055 and BIG-IP APM CVE-2025-53521 • Supply chain follow-up: renewed attention on TeamPCP’s WAV/MsBuild delivery technique • Incident claim: alleged large-scale breach of Spain’s Feníe Energía

    @Team_D4rkn3ttz

    1 Apr 2026

    286 Impressions

    0 Retweets

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    4 Replies

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  4. 💡IR/CERT Morning Brief (4/1) • Priority issues: NetScaler CVE-2026-3055 and BIG-IP APM CVE-2025-53521 • Supply chain follow-up: renewed attention on TeamPCP’s WAV/MsBuild delivery technique • Incident claim: alleged large-scale breach of Spain’s Feníe Energía •

    @Team_D4rkn3ttz

    1 Apr 2026

    5 Impressions

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  5. ⚠️Citrix NetScalerの最近の脆弱性に関連する偵察活動が確認される:CVE-2026-3055 🚨CISA、BIG-IP APMシステムのRCE脆弱性(CVE-2025-53521)をKEVカタログに追加 〜サイバーセキュリティ週末の話題〜 https://t.co/1r2usvLTuX

    @MachinaRecord

    30 Mar 2026

    278 Impressions

    0 Retweets

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  6. 🧵 Doppelschlag bei kritischer Netzwerk-Infrastruktur: CVE-2025-53521 und CVE-2026-3055 bedrohen Tausende Unternehmen **Die vergangenen 48 Stunden haben zwei kritische Schwachstellen in fundamentaler Enterprise-Netzwerk-Infrastruktur ins Rampenlicht gerückt: F5 BIG-... https:

    @dirkalthausinv

    30 Mar 2026

    157 Impressions

    0 Retweets

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  7. CitrixBleed happened in 2023. LockBit used it to hit Boeing and ICBC. CitrixBleed2 happened in 2025. Salt Typhoon used it to backdoor a European telecom. Citrix just patched CVE-2026-3055. Same vulnerability class. Same product. CVSS 9.3. No auth required. Rapid7 and watchTowr

    @Atarussecurity

    27 Mar 2026

    105 Impressions

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  8. Top 5 Trending CVEs: 1 - CVE-2026-27522 2 - CVE-2026-3055 3 - CVE-2025-58718 4 - CVE-2026-20963 5 - CVE-2026-21858 #cve #cvetrends #cveshield #cybersecurity https://t.co/4Fua3CAN6W

    @CVEShield

    26 Mar 2026

    238 Impressions

    0 Retweets

    2 Likes

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Configurations

  1. Issue summary: The DTLS retransmission logic does not correctly handle a handshake message write that is suspended part-way through. The retransmitted message can be read past the message buffer and the retransmission overwrites the internal state the suspended write needs to resume correctly. Impact summary: The retransmitted message can disclose a heap memory to the peer as plaintext handshake data or cause a crash and a Denial of Service when the read reaches an unmapped memory region. CWE: CWE-125: Out-of-bounds Read Description: DTLS handshake messages can be written out in multiple fragments, and a write can suspend mid-message (returning WANT_WRITE) if the underlying transport temporarily cannot accept more data. While such a write is suspended, the DTLS retransmission timer may independently fire and ask the retransmission logic to resend an earlier, already-acknowledged-as-sent message from its retransmit queue. The retransmission logic reused the same internal buffer and position tracking as the message that was still being written, without resetting the position back to the start of the message being retransmitted. As a result the retransmission was read starting from wherever the suspended write had left off, producing a mislabelled message whose body was leftover bytes from the other, larger message still in flight - content that was never meant to be sent at that point, and which could run past the end of the allocated buffer. Separately, even when the retransmission is positioned correctly, allowing it to run to completion while another write is suspended overwrites the same shared bookkeeping that the suspended write depends on to resume. When the application later resumes the suspended write (via a subsequent SSL_read(), SSL_write(), SSL_accept(), or SSL_connect() call), it finds that bookkeeping in a state inconsistent with the message and aborts the process in a debugging build. The fix resets the retransmission's read position to the start of the message before resending, and skips retransmission entirely whenever a handshake write is still suspended, deferring to the next call that resumes it instead. FIPS impact: no The affected code is outside the FIPS module boundary.•CVE-2026-84782