Security readout for executives and security teams
CVE-2026-3256 affects the Perl HTTP::Session library before version 0.54. It can create session IDs from predictable inputs instead of cryptographically secure randomness. If an application relies on these default IDs, an attacker may be able to guess valid sessions and impersonate users. Exposure is limited to Perl applications using HTTP::Session versions before 0.54, especially those relying on the default SHA1 session ID generator or the included MD5 generator. Internet-facing applications with authenticated user sessions carry the highest business risk. Prioritize remediation for internet-facing Perl applications that manage logins or sensitive sessions. The issue can undermine authentication boundaries, but urgency should be scoped to confirmed use of affected HTTP::Session versions and vulnerable ID generators. Mitigation focus: Inventory Perl applications using the http-session package.; Upgrade HTTP::Session to version 0.54 or later where applicable.; Review vendor release notes and MetaCPAN security guidance..
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-338: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCWE-340: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2026-3256 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- Source timelineCPANSec
CVE-2026-3256 published
- CVE publishedCVE Program
The CVE record was published.
- Source timelineCPANSec
HTTP::Session version 0.54 released
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://metacpan.org/release/KTAT/http-session-0.53/source/lib/HTTP/Session/ID/SHA1.pmCVE reference, CPANSec
- https://metacpan.org/release/KTAT/http-session-0.53/source/lib/HTTP/Session/ID/MD5.pmCVE reference, CPANSec
- https://security.metacpan.org/docs/guides/random-data-for-security.htmlCVE reference, CPANSec · technical-description
- https://metacpan.org/release/TOKUHIROM/http-session-0.54/changesCVE reference, CPANSec · release-notes
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Generation of Predictable Numbers or Identifiers
Generation of Predictable Numbers or Identifiers represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.