How severe is CVE-2026-3255?

CVE-2026-3255 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability low.

Is CVE-2026-3255 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (34th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-3255?

CVE-2026-3255 affects Tokuhirom Http. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-3255?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-3255 have an EU (EUVD) identifier?

Yes. CVE-2026-3255 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-9063.

When was CVE-2026-3255 published?

CVE-2026-3255 was published on 2026-02-27 and last updated on 2026-06-17.

CVE-2026-3255

CVE-2026-3255 is a medium-severity vulnerability in Tokuhirom Http with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-338.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
EPSS exploit prediction: 0% (34th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-9063
Weakness: CWE-338
Affected product: Tokuhirom Http
Published: 2026-02-27
Last modified: 2026-06-17

Description

HTTP::Session2 versions before 1.12 for Perl for Perl may generate weak session ids using the rand() function. The HTTP::Session2 session id generator returns a SHA-1 hash seeded with the built-in rand function, the 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. HTTP::Session2 after version 1.02 will attempt to use the /dev/urandom device to generate a session id, but if the device is unavailable (for example, under Windows), then it will revert to the insecure method described above.

Frequently asked questions

What is CVE-2026-3255?: HTTP::Session2 versions before 1.12 for Perl for Perl may generate weak session ids using the rand() function. The HTTP::Session2 session id generator returns a SHA-1 hash seeded with the built-in rand function, the 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. HTTP::Session2 after version 1.02 will attempt to use the /dev/urandom device to generate a session id, but if the device is unavailable (for example, under Windows), then it will revert to the insecure method described above.
How severe is CVE-2026-3255?: CVE-2026-3255 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability low.
Is CVE-2026-3255 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (34th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-3255?: CVE-2026-3255 affects Tokuhirom Http. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-3255?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-3255 have an EU (EUVD) identifier?: Yes. CVE-2026-3255 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-9063.
When was CVE-2026-3255 published?: CVE-2026-3255 was published on 2026-02-27 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:tokuhirom:http\:\:session2:*:*:*:*:*:perl:*:*

Other CWE-338 vulnerabilities

CVE-2026-56141 — Critical (CVSS 9.8): In JetBrains Hub before 2026.1.13757, 2025.3.148033, 2025.2.148048, 2025.1.148120, 2024.3.148430, 2024.2.148429 account…
CVE-2026-3256 — Critical (CVSS 9.8): HTTP::Session versions before 0.54 for Perl defaults to using insecurely generated session ids. HTTP::Session defaults…
CVE-2025-15604 — Critical (CVSS 9.8): Amon2 versions before 6.17 for Perl use an insecure random_string implementation for security functions. In versions…
CVE-2025-40926 — Critical (CVSS 9.8): Plack::Middleware::Session::Simple versions before 0.05 for Perl generates session ids insecurely. The default session…
CVE-2026-2439 — Critical (CVSS 9.8): Concierge::Sessions versions from 0.8.1 before 0.8.5 for Perl generate insecure session ids. The generate_session_id…
CVE-2025-15578 — Critical (CVSS 9.8): Maypole versions from 2.10 through 2.13 for Perl generates session ids insecurely. The session id is seeded with the…

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