How severe is CVE-2019-25025?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Is CVE-2019-25025 known to be exploited?

3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Rubyonrails Active Record Session Store

CVE-2019-25025

The activerecord-session_store (aka Active Record Session Store) component through 1.1.3 for Ruby on Rails does not use a constant-time approach when delivering information about whether a guessed session ID is valid. Consequently, remote attackers can leverage timing discrepancies to achieve a correct guess in a relatively short amount of time. This is a related issue to CVE-2019-16782.

Published 2021-03-05 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.018 (78.1th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 78th percentile — 78.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.018 · newest: 0.018 · change: 0.000

Affected products

Rubyonrails Active Record Session Store

Public proof-of-concept exploits

References

github.com/rails/activerecord-session_store/pull/151 (Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2019-25025?: CVE-2019-25025 is a medium-severity vulnerability in Rubyonrails Active Record Session Store. CVSS score: 5.3/10. Published 2021-03-05.
How severe is CVE-2019-25025?: Medium severity. CVSS v3 base score is 5.3 out of 10.
Is CVE-2019-25025 known to be exploited?: 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.