HTTP::Session versions through 0.53 for Perl defaults to using insecurely generated session ids

MITRE NVD CVE.ORG Print: PDF PDF

Summary

CVECVE-2026-3256
StatePUBLISHED
AssignerCPANSec
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-03-28 19:16:56 UTC
Updated2026-04-01 15:23:23 UTC
DescriptionHTTP::Session versions through 0.53 for Perl defaults to using insecurely generated session ids. HTTP::Session defaults to using HTTP::Session::ID::SHA1 to generate session ids using a SHA-1 hash seeded with the built-in rand function, the high resolution epoch time, and the PID. The PID will come from a small set of numbers, and the epoch time may be guessed, if it is not leaked from the HTTP Date header. The built-in rand function is unsuitable for cryptographic usage. The distribution includes HTTP::session::ID::MD5 which contains a similar flaw, but uses the MD5 hash instead.

Risk And Classification

Primary CVSS: v3.1 9.8 CRITICAL from [email protected]

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

EPSS: 0.000160000 probability, percentile 0.036110000 (date 2026-04-01)

Problem Types: CWE-338 | CWE-340 | CWE-340 CWE-340 Generation of Predictable Numbers or Identifiers | CWE-338 CWE-338 Use of Cryptographically Weak Pseudo-Random Number Generator

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
3.1ADPDECLARED9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Ktat Http \ session All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA KTAT HTTPSession affected 0.53 custom Not specified

References

ReferenceSourceLinkTags
metacpan.org/release/KTAT/http-session-0.53/source/lib/HTTP/Session/ID/SHA... 9b29abf9-4ab0-4765-b253-1875cd9b441e metacpan.org Product
metacpan.org/release/KTAT/http-session-0.53/source/lib/HTTP/Session/ID/MD5.pm 9b29abf9-4ab0-4765-b253-1875cd9b441e metacpan.org Product
www.openwall.com/lists/oss-security/2026/03/28/5 af854a3a-2127-422b-91ae-364da2661108 www.openwall.com Mailing List, Third Party Advisory
security.metacpan.org/docs/guides/random-data-for-security.html 9b29abf9-4ab0-4765-b253-1875cd9b441e security.metacpan.org Third Party Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Additional Advisory Data

Workarounds

CNA: Users on systems with a /dev/urandom device should configure the module to use HTTP::Session::ID::Urandom. Users on systems without a /dev/urandom (such as Windows) device will need to create custom ID modules that make use of module such as Crypt::SysRandom or Crypt::URandom.

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