What is the CVSS score of CVE-2026-41564?

CVE-2026-41564 has a CVSS 3.1 base score of 7.5 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. EPSS exploitation probability: 0.0%.

How to fix or mitigate CVE-2026-41564?

Within 24 hours: inventory all Perl applications using CryptX library and identify preforking server deployments. Within 7 days: upgrade CryptX to version 0.088 or later across all affected systems and restart all application services. Within 30 days: conduct audit of any ECDSA/DSA signatures generated by affected instances prior to patching to determine if key recovery occurred.

CryptX for Perl CVE-2026-41564

Q: Which versions of CryptX for Perl are affected by CVE-2026-41564?

CVE-2026-41564 affects CryptX for Perl and enables attackers to recover private signing keys through cryptographic nonce reuse in preforking web server environments like Starman.. A patch is available.

EUVD-2026-25201 HIGH

Incorrect Usage of Seeds in Pseudo-Random Number Generator (PRNG) (CWE-335)

2026-04-23 CPANSec

Information Disclosure Cryptx

7.5

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

7.5 HIGH

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

SUSE

HIGH

qualitative

Primary rating from NVD.

CVSS VectorNVD

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Lifecycle Timeline

Re-analysis Queued

Apr 24, 2026 - 14:52 vuln.today

cvss_changed

Analysis Generated

Apr 23, 2026 - 14:37 vuln.today

CVSS changed

Apr 23, 2026 - 14:37 NVD

7.5 (None) 7.5 (HIGH)

EUVD ID Assigned

Apr 23, 2026 - 08:00 euvd

EUVD-2026-25201

Analysis Generated

Apr 23, 2026 - 08:00 vuln.today

Patch released

Apr 23, 2026 - 08:00 nvd

Patch available

CVE Published

Apr 23, 2026 - 07:29 nvd

HIGH 7.5

DescriptionCVE.org

CryptX versions before 0.088 for Perl do not reseed the Crypt::PK PRNG state after forking.

The Crypt::PK::RSA, Crypt::PK::DSA, Crypt::PK::DH, Crypt::PK::ECC, Crypt::PK::Ed25519 and Crypt::PK::X25519 modules seed a per-object PRNG state in their constructors and reuse it without fork detection. A Crypt::PK::* object created before fork() shares byte-identical PRNG state with every child process, and any randomized operation they perform can produce identical output, including key generation. Two ECDSA or DSA signatures from different processes are enough to recover the signing private key through nonce-reuse key recovery.

This affects preforking services such as the Starman web server, where a Crypt::PK::* object loaded at startup is inherited by every worker process.

AnalysisAI

PRNG state reuse across forked processes in CryptX for Perl allows remote attackers to recover private signing keys through cryptographic nonce-reuse attacks. When Crypt::PK objects are created before fork() in preforking web servers like Starman, every child process inherits identical PRNG state, causing duplicate randomness in cryptographic operations. Two ECDSA or DSA signatures generated by different worker processes are sufficient to mathematically recover the private key. EPSS exploitation probability is low (0.02%), but CISA SSVC framework confirms proof-of-concept availability and automatable exploitation. Vendor patch released in CryptX 0.088.

Technical ContextAI

CryptX is a Perl cryptographic library providing implementations of RSA, DSA, ECDSA, Ed25519, X25519, and Diffie-Hellman through its Crypt::PK::* module family (CPE: cpe:2.3:a:mik:cryptx). The vulnerability stems from CWE-335 (Incorrect Usage of Seeds in Pseudo-Random Number Generator) - specifically, failure to reseed the PRNG after process forking. In Unix/Linux preforking architectures, a parent process initializes resources then spawns child workers via fork(), which inherit memory state including PRNG seeds. Without fork detection, cryptographic operations requiring randomness (nonces for ECDSA/DSA signatures, ephemeral keys for ECDH) generate identical values across processes. ECDSA and DSA signature schemes are deterministically broken by nonce reuse: solving two equations with the same nonce k but different messages reveals the private key d through basic algebra. This is a well-known cryptanalytic attack (e.g., the 2010 PlayStation 3 signing key compromise). The vulnerability is particularly dangerous in preforking web servers where a single CryptX object loaded during startup is shared by all workers handling concurrent client requests.

RemediationAI

Upgrade to CryptX version 0.088 or later, which implements fork detection and automatic PRNG reseeding (patch commit: https://github.com/DCIT/perl-CryptX/commit/9a1dd3e0c27d68e32450be5538b864c2b115ee15.patch, release: https://metacpan.org/release/MIK/CryptX-0.088). For environments where immediate upgrade is not feasible, implement the following compensating controls with noted trade-offs: (1) Create new Crypt::PK::* objects within each child process after fork() rather than inheriting from parent - requires application code changes and increases memory overhead per worker. (2) Migrate cryptographic operations to a separate non-forking service accessed via IPC/RPC - adds architectural complexity and latency but isolates the vulnerability. (3) Replace CryptX with alternative Perl crypto libraries that implement fork-safe PRNG handling (e.g., Crypt::OpenSSL modules) - requires code refactoring and compatibility testing. (4) For signature verification only (not generation), the vulnerability does not apply; review code to ensure affected workers never perform signing operations - requires careful audit and enforcement. Each workaround carries operational risk; vendor patch is the definitive solution.