GUIMARD Apache::Session::Generate::SHA256 up to 1.3.18 on Perl rand generation of predictable numbers or identifiers

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
5.0$0-$5k0.00

Summaryinfo

A vulnerability has been found in GUIMARD Apache::Session::Generate::SHA256 up to 1.3.18 on Perl and classified as problematic. Impacted is the function rand. This manipulation causes generation of predictable numbers or identifiers. This vulnerability is handled as CVE-2026-8503. The attack can be initiated remotely. There is not any exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability has been found in GUIMARD Apache::Session::Generate::SHA256 up to 1.3.18 on Perl and classified as problematic. Affected by this vulnerability is the function rand. The manipulation with an unknown input leads to a generation of predictable numbers or identifiers vulnerability. The CWE definition for the vulnerability is CWE-340. The product uses a scheme that generates numbers or identifiers that are more predictable than required. As an impact it is known to affect confidentiality. The summary by CVE is:

Apache::Session::Generate::SHA256 versions before 1.3.19 for Perl create insecure session ids. Apache::Session::Generate::SHA256 generated session ids insecurely. The default session id generator returns a SHA-256 hash of the built-in rand() function, the epoch time, and the PID, that is hashed again. These are predictable, low-entropy sources. Predicable session ids could allow an attacker to gain access to systems. Note that version 1.3.19 has a fallback without warning to use insecure session generation method if the call to Crypt::URandom::urandom fails. However, this is unlikely as Crypt::URandom is a hardcoded requirement of the module. This issue is similar to CVE-2025-40931 for Apache::Session::Generate::MD5.

It is possible to read the advisory at metacpan.org. This vulnerability is known as CVE-2026-8503 since 05/13/2026. The exploitation appears to be difficult. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1600.001 according to MITRE ATT&CK.

The vulnerability scanner Nessus provides a plugin with the ID 316616 (Fedora 44 : perl-Apache-Session-Browseable (2026-19d80281b7)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 1.3.19 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (316616). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Vendor

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.1
VulDB Meta Temp Score: 5.0

VulDB Base Score: 3.7
VulDB Temp Score: 3.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

ADP CISA Base Score: 6.5
ADP CISA Vector: 🔒

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Generation of predictable numbers or identifiers
CWE: CWE-340 / CWE-331 / CWE-330
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Nessus ID: 316616
Nessus Name: Fedora 44 : perl-Apache-Session-Browseable (2026-19d80281b7)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Apache::Session::Generate::SHA256 1.3.19

Timelineinfo

05/13/2026 CVE reserved
05/15/2026 +2 days Advisory disclosed
05/15/2026 +0 days VulDB entry created
05/26/2026 +11 days VulDB entry last update

Sourcesinfo

Advisory: metacpan.org
Status: Confirmed

CVE: CVE-2026-8503 (🔒)
GCVE (CVE): GCVE-0-2026-8503
GCVE (VulDB): GCVE-100-364171

Entryinfo

Created: 05/15/2026 13:51
Updated: 05/26/2026 02:07
Changes: 05/15/2026 13:51 (55), 05/21/2026 06:12 (11), 05/26/2026 02:07 (2)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Interested in the pricing of exploits?

See the underground prices here!