Cyber Resilience

CVE-2026-19566

Published
12 August 2026
Modified
26 August 2026
CVSS Score v3.1 7.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0035 27th percentile
Risk Priority 57 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-19566 is a high-severity Memory Allocation with Excessive Size Value (CWE-789) vulnerability. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 27th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and SC-6 (Resource Availability) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

Net::CIDR::Set versions before 0.23 for Perl allow memory exhaustion and malformed set ranges via unbounded IPv6 prefix lengths. The _encode method accepts any prefix length matching `(0|[1-9][0-9]*)` and passes it to _width2bits(), which builds the mask as `'1' x ($width…

more

+ 8)`, one character per bit. The _inc() method then unpacks the packed mask into a Perl array of one scalar per byte, so the prefix length alone sets the allocation size: `::/100000000` builds a 100 MB string and a 12.5 million element array. The value being tested is parsed, not just the configured ranges: contains() builds a set from its argument, and _guess_coder() tries the IPv4 coder and then the IPv6 coder, so an IPv4-only set expands an oversized IPv6 prefix length before the mixed address width check rejects it. Any caller that passes untrusted input to contains() or add() can exhaust process memory. A prefix length above 128 is also stored as a range that does not match the requested block: 2001:db8::/129 stringifies back unchanged, contains() of its own base address returns false, and removing it from a set drops the base address while the set still prints as covering it.

CWE(s)
CWE-789CWE-1284

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
attack.mitre.org →
T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-47667Shared CWE-1284, CWE-789
CVE-2026-54890Shared CWE-1284, CWE-789
CVE-2026-55392Shared CWE-1284
CVE-2025-36094Shared CWE-1284
CVE-2023-31310Shared CWE-1284
CVE-2026-49078Shared CWE-1284
CVE-2026-59532Shared CWE-1284
CVE-2026-59694Shared CWE-1284
CVE-2024-35963Shared CWE-1284
CVE-2026-27171Shared CWE-1284

Affected Assets

—
Set
inferred from references and description; NVD did not file a CPE for this CVE

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)
  • V6.7.2
  • V1.4.2
  • V2.1.1
  • V2.2.1

Mitigating Controls (NIST 800-53 r5) AI

SI-10 Information Input Validation good match

Input validation directly rejects or bounds untrusted size values before any allocation occurs.

SC-6 Resource Availability partial match

Resource quotas and priority allocation limit the system-wide impact of an oversized request.

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

Secure SDLC practices directly prevent coding flaws that trust unvalidated size values for allocations.

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.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development can detect and block excessive allocation flaws before deployment.

A.8.25 Secure development life cycle partial match
prevents

Secure development lifecycle includes input validation and size checks that prevent unbounded allocations.

A.8.26 Application security requirements partial match
prevents

Application security requirements mandate bounds checking on size parameters to avoid excessive memory allocation.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles require resource-limit enforcement that mitigates uncontrolled memory requests.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly prohibit allocating memory from untrusted size values without validation.

References