CVE-2026-5085
Predictable Session ID Vulnerability in Solstice::Session Perl Module
Publication date: 2026-04-13
Last updated on: 2026-04-23
Assigner: CPANSec
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| mcrawfor | solstice | * |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-338 | The product uses a Pseudo-Random Number Generator (PRNG) in a security context, but the PRNG's algorithm is not cryptographically strong. |
| CWE-340 | The product uses a scheme that generates numbers or identifiers that are more predictable than required. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability affects Solstice::Session versions through 1440 for Perl, where session IDs are generated insecurely.
The method generating session IDs uses an MD5 digest seeded by predictable values: the epoch time, a random hash reference, the built-in rand() function, and the process ID.
Because these seed values are predictable or guessable (for example, epoch time can be guessed if not leaked in HTTP headers, the hash references contain predictable content, rand() is seeded with only 16 bits, and process IDs come from a small set), the resulting session IDs can be predicted.
Predictable session IDs allow attackers to potentially guess valid session identifiers and gain unauthorized access to systems.
How can this vulnerability impact me? :
Because session IDs are predictable, an attacker could guess or forge valid session identifiers.
This could allow unauthorized access to user sessions, leading to potential data breaches, impersonation of legitimate users, and unauthorized actions within the affected system.
How can this vulnerability be detected on my network or system? Can you suggest some commands?
This vulnerability involves predictable session IDs generated by the Solstice::Session and Solstice::Subsession Perl modules using MD5 digests seeded with predictable values such as epoch time, process ID, and a weak random number generator.
To detect this vulnerability on your system, you can monitor session IDs used by the application and check for predictability or weak randomness. Specifically, you can capture session cookies and analyze their values for patterns or reuse.
- Use network traffic capture tools like tcpdump or Wireshark to capture HTTP traffic and extract session cookies.
- Example command to capture HTTP traffic on port 80 and save to a file: tcpdump -i any -s 0 -w capture.pcap port 80
- Use tools like tshark or Wireshark to filter and extract cookie headers from the capture file.
- Analyze the session ID values for predictability, such as repeated patterns, timestamps, or low entropy.
Additionally, reviewing application logs or debugging output for session ID generation details may help identify the use of the vulnerable Solstice::Session or Solstice::Subsession modules.
What immediate steps should I take to mitigate this vulnerability?
Immediate mitigation steps focus on preventing attackers from exploiting predictable session IDs to gain unauthorized access.
- Update or patch the Solstice::Session and Solstice::Subsession modules to versions that use secure, cryptographically strong session ID generation methods instead of MD5 seeded with predictable values.
- If updating is not immediately possible, consider implementing additional session management controls such as regenerating session IDs after login and enforcing short session timeouts.
- Ensure that HTTP headers like Date do not leak epoch time information that could aid attackers in guessing session IDs.
- Monitor and log suspicious session activity to detect potential exploitation attempts.
Longer term, replace the weak random number generation and MD5-based session ID creation with a secure cryptographic random number generator.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
The vulnerability in Solstice::Session and Solstice::Subsession involves insecure generation of session IDs using predictable inputs such as epoch time, a random hash reference, the built-in rand() function, and the process ID. This predictability could allow attackers to guess session IDs and gain unauthorized access to systems.
Such unauthorized access risks compromising user data confidentiality and integrity, which are critical requirements under common standards and regulations like GDPR and HIPAA. Failure to adequately protect session identifiers may lead to violations of these regulations' mandates on protecting personal and sensitive information.
Therefore, this vulnerability could negatively impact compliance by exposing systems to session hijacking attacks, potentially resulting in unauthorized data access and breaches of regulatory requirements.