Cyber Resilience

CVE-2021-22894

RCE in Ivanti Connect Secure 9.0 … 9.1

CISA KEVActive ExploitationEUVD ExploitedRCEMemory Safety
Published
27 May 2021
Modified
18 December 2025
KEV Added
03 November 2021
Patch / advisory
CVSS Score v3.1 8.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.41 99th percentile
Risk Priority 90 floored blend · peak EPSS

Summary

CVE-2021-22894 is a high-severity Code Injection (CWE-94) vulnerability in Ivanti Connect Secure. Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Command and Scripting Interpreter (T1059); ranked in the top 1% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

A buffer overflow vulnerability exists in Pulse Connect Secure versions prior to 9.1R11.4. The flaw, tracked under CWE-94 and CWE-119, resides in the component responsible for processing meeting rooms and permits memory corruption that can lead to arbitrary code execution.

A remote authenticated attacker with low privileges can exploit the issue over the network by submitting a maliciously crafted meeting room. Successful exploitation grants the attacker the ability to run arbitrary code as the root user, resulting in full compromise of confidentiality, integrity, and availability as reflected in the CVSS 3.1 base score of 8.8.

The vendor advisory SA44784 states that the vulnerability is resolved in Pulse Connect Secure 9.1R11.4 and later releases. CISA includes CVE-2021-22894 in its catalog of known exploited vulnerabilities, confirming observed in-the-wild activity.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

A buffer overflow vulnerability exists in Pulse Connect Secure before 9.1R11.4 allows a remote authenticated attacker to execute arbitrary code as the root user via maliciously crafted meeting room.

CWE(s)
KEV Date Added
03 November 2021

Related Threats

MITRE ATT&CK Enterprise Techniques

T1059 Command and Scripting Interpreter Execution
Adversaries may abuse command and script interpreters to execute commands, scripts, or binaries.
T1059.001 PowerShell Execution
Adversaries may abuse PowerShell commands and scripts for execution.
T1059.002 AppleScript Execution
Adversaries may abuse AppleScript for execution.
T1059.004 Unix Shell Execution
Adversaries may abuse Unix shell commands and scripts for execution.
T1059.005 Visual Basic Execution
Adversaries may abuse Visual Basic (VB) for execution.
T1059.006 Python Execution
Adversaries may abuse Python commands and scripts for execution.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2020-8243Same product: Ivanti Connect Secureboth on KEV
CVE-2021-22900Same product: Ivanti Connect Secureboth on KEV
CVE-2024-10644Same product: Ivanti Connect Secure
CVE-2020-8218Same product: Ivanti Connect Secureboth on KEV
CVE-2023-41724Same product class: VPN / SSL gateway
CVE-2023-6548Same product class: VPN / SSL gatewayboth on KEV
CVE-2023-3519Same product class: VPN / SSL gatewayboth on KEV
CVE-2021-44529Same vendor: Ivantiboth on KEV
CVE-2025-7775Same product class: VPN / SSL gatewayboth on KEV
CVE-2025-6543Same product class: VPN / SSL gatewayboth on KEV

Affected Assets

ivanti
connect secure
9.0, 9.1

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V17.3.2
  • V1.3.1

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-94 CWE-119

Directly prevents execution of attacker-supplied code written into data memory regions.

addresses: CWE-119

Ongoing control assessments and code testing (static/dynamic analysis, fuzzing) surface memory buffer restriction failures, which are then remediated before release.

addresses: CWE-119

Managed runtimes used by platform-independent applications (e.g., JVM, CLR) enforce memory safety, preventing most buffer overflows that require direct memory manipulation.

addresses: CWE-94

Makes persistent code injection into loaded programs impossible when the executable image itself resides on hardware-protected read-only media.

addresses: CWE-94

Dynamically generated code can be produced and executed inside the isolated chamber, preventing host compromise from code-injection payloads.

addresses: CWE-94

Validates inputs used in dynamic code generation to block injected directives.

addresses: CWE-119

Detects exploitation attempts that produce memory corruption, crashes, or anomalous behavior.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

PR.PS-06's SDLC practices directly target injection flaws via secure coding and testing (mostly), yet as a single broad outcome it leaves many code-generation specifics unaddressed (partial).

ID.RA-01 partial match
prevents

Vulnerability scanning and code analysis directly surface buffer-boundary flaws.

ID.RA-08 partial match
prevents

Receiving and triaging vulnerability disclosures commonly includes buffer-related reports.

PR.AT-02 partial match
prevents

Developer training on secure coding reduces introduction of memory-buffer errors.

PR.PS-02 partial match
prevents

Patching replaces vulnerable code containing buffer-boundary defects.

PR.DS-10 none match
prevents

PR.DS-10 protects runtime data confidentiality/integrity but has no bearing on neutralizing externally influenced input during code generation, so neither direction shows any preventive effect.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing in development catches out-of-bounds accesses before release, covering most instances of the weakness.

prevents

Secure development lifecycle mandates memory-safety practices that directly prevent buffer-boundary violations.

prevents

Application security requirements can specify memory-safety rules, but do not prescribe implementation details.

prevents

Secure architecture and engineering principles include memory-safe design patterns that mitigate buffer overflows.

prevents

Banning unapproved code samples and unauthenticated web services, combined with secure-coding standards and SAST, prevents the dynamic generation or inclusion of attacker-supplied code.

none

Controls that restrict unauthorized or malicious code from being introduced via external networks or removable media limit opportunities for an attacker to inject and execute arbitrary code.

References