Is CVE-2026-8503 in the CISA KEV catalog?

No. CVE-2026-8503 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-8503?

CVE-2026-8503 has a CVSS v3 base score of 6.5 (MEDIUM).

What is the EPSS score for CVE-2026-8503?

CVE-2026-8503 has an EPSS score of 0.24% (15th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-8503?

Upgrade libapache-session-browseable-perl on debian unstable to 1.3.19-1 or later.

CVE & CISA-KEV Catalog

CVE-2026-8503

MEDIUM

6.5

CVSS v3

NVD

Description

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.

CWE-338 CWE-340

How to fix

Remediation Available

libapache-session-browseable-perlDebian

Fixed in:1.3.19-1CVE-2026-8503

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityLow

IntegrityLow

AvailabilityNone

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

Exploit Intelligence

0.24%probability of exploitation in 30 days

15thpercentile

Low risk: more likely to be exploited than 15% of all known CVEs.

References

Patch1

github.com

Third-Party Advisory2

Release Notes1

metacpan.org

Product1

metacpan.org

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-18.