CVE-2026-13577 (GCVE-0-2026-13577)
Vulnerability from cvelistv5 – Published: 2026-07-20 07:11 – Updated: 2026-07-22 12:00
VLAI
EPSS
VEX
Title
Dancer2 versions through 2.1.0 for Perl generate insecure session ids when required CSPRNG modules are unavailable
Summary
Dancer2 versions through 2.1.0 for Perl generate insecure session ids when required CSPRNG modules are unavailable.
Dancer2::Core::Role::SessionFactory::generate_id silently falls back to a built-in rand-derived session id unless both Math::Random::ISAAC::XS and Crypt::URandom are available.
The fallback session id is generated from a SHA-1 hash of a call to the built-in rand function, the absolute path of the Dancer2::Core::Role::SessionFactory module, an internal counter, the process id, the module instance memory address, and a shuffled string of characters (using the List::Util::shuffle function, which also uses the built-in rand function).
These are all low-entropy and easily guessed sources.
The built-in rand() function is seeded with 32-bits and considered unsuitable for security applications.
Predictable session ids could allow an attacker to gain access to systems.
Severity
8.2 (High)
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
Assigner
References
2 references
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
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