CVE-2026-30909

Critical

Published: 08 March 2026

Published

08 March 2026

Modified

18 March 2026

KEV Added

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Patch

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CVSS Score 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Score 0.0003 8.1th percentile

Risk Priority 20 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-30909 is a critical-severity Integer Overflow or Wraparound (CWE-190) vulnerability in Timlegge Crypt\. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 8.1th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified are NIST 800-53 RA-5 (Vulnerability Monitoring and Scanning) and SI-2 (Flaw Remediation).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploit Public-Facing Application (T1190) and 4 other techniques. What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

SI-2 Flaw Remediation good match

prevent

Timely remediation through patching the integer overflow in Crypt::NaCl::Sodium functions directly prevents buffer underallocation and exploitation.

SI-10 Information Input Validation partial match

prevent

Validating input lengths prior to invoking affected functions like bin2hex and encrypt prevents triggering the integer wraparound condition.

RA-5 Vulnerability Monitoring and Scanning good match

detect

Vulnerability scanning identifies systems using vulnerable Crypt::NaCl::Sodium versions through 2.002, enabling targeted remediation.

MITRE ATT&CK Enterprise TechniquesAI

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 →

T1068 Exploitation for Privilege Escalation Privilege Escalation

Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.

attack.mitre.org →

T1499.004 Application or System Exploitation Impact

Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.

attack.mitre.org →

Why these techniques?

Remote unauthenticated attacker supplying crafted large inputs to affected crypto functions (encrypt/seal/etc.) can trigger memory corruption or crashes in applications using the library, directly enabling exploitation of public-facing apps/remote services for RCE, priv-esc, or DoS.

Confidence: MEDIUM · MITRE ATT&CK Enterprise v18.1

NVD Description

Crypt::NaCl::Sodium versions through 2.002 for Perl has potential integer overflows. bin2hex, encrypt, aes256gcm_encrypt_afternm and seal functions do not check that output size will be less than SIZE_MAX, which could lead to integer wraparound causing an undersized output buffer. Encountering this…

issue is unlikely as the message length would need to be very large. For bin2hex() the bin_len would have to be > SIZE_MAX / 2 For encrypt() the msg_len would need to be > SIZE_MAX - 16U For aes256gcm_encrypt_afternm() the msg_len would need to be > SIZE_MAX - 16U For seal() the enc_len would need to be > SIZE_MAX - 64U

Deeper analysisAI

CVE-2026-30909 is an integer overflow vulnerability (CWE-190) affecting Crypt::NaCl::Sodium versions through 2.002, a Perl module implementing the NaCl cryptography library. The issue resides in the bin2hex, encrypt, aes256gcm_encrypt_afternm, and seal functions, which fail to verify that the required output size remains below SIZE_MAX before allocation. This can trigger integer wraparound, resulting in an undersized output buffer. The vulnerability carries a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), reflecting severe potential impacts despite practical constraints.

Any remote, unauthenticated attacker able to supply inputs to affected functions could exploit this vulnerability. Exploitation requires extremely large input lengths—for bin2hex, binary length exceeding SIZE_MAX / 2; for encrypt and aes256gcm_encrypt_afternm, message length over SIZE_MAX - 16U; and for seal, encrypted length surpassing SIZE_MAX - 64U—making it unlikely in typical scenarios. Successful exploitation could lead to buffer underallocation, potentially causing memory corruption, application crashes, or incorrect cryptographic operations that compromise confidentiality, integrity, and availability.

Mitigation is available via a patch in pull request #24 at https://github.com/cpan-authors/crypt-nacl-sodium/pull/24.patch, which addresses the output size checks in the vulnerable functions. The referenced source code lines from the vulnerable version 2.002 (e.g., Sodium.xs at lines 2116, 2310, 3304, and 942 on metacpan.org) highlight the exact locations of the flaws for verification and patching. Security practitioners should update to a patched version beyond 2.002.