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CVE-2023-30861

25
FAUCET Score

CVE-2023-30861 is a high-severity vulnerability affecting Flask web applications, specifically versions prior to 2.3.2 and 2.2.5. It allows a caching proxy to serve one client's sensitive session data, including cookies, to other clients under specific conditions, potentially leading to information disclosure. The vulnerability has a CVSS score of 7.5 (High) due to its network-based attack vector and low attack complexity, with a high impact on confidentiality. There is currently no evidence of active exploitation, public exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
< 2.2.5CPE matchmatch criteria
cpe:2.3:a:palletsprojects:flask:*:*:*:*:*:*:*:*
>= 2.3.0, < 2.3.2CPE matchmatch criteria
cpe:2.3:a:palletsprojects:flask:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.22%
Probability of exploitation in next 30 days
EPSS Percentile
65.4%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0122 is in the 44th percentile among its peer group of 51,506 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (13)

github_advisorypatch availablevia nvd_reference
View patch
pippatch availablevia ghsa
Product: flaskFixed in: 2.3.2
pippatch availablevia ghsa
Product: flaskFixed in: 2.2.5
redhatpatch availablevia redhat_api
Product: Ironic content for Red Hat OpenShift Container Platform 4.11Fixed in: python-flask-1:1.1.2-6.el8
View patch
redhatpatch availablevia redhat_api
Product: Ironic content for Red Hat OpenShift Container Platform 4.12Fixed in: python-flask-1:2.0.1-3.el9
View patch
redhatpatch availablevia redhat_api
Product: Ironic content for Red Hat OpenShift Container Platform 4.13Fixed in: python-flask-2:2.0.1-4.el9.2
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7 ExtrasFixed in: python-flask-1:0.10.1-7.el7_9
View patch
redhatpatch availablevia redhat_api
Product: Red Hat OpenStack Platform 16.1Fixed in: python-flask-1:1.0.2-8.el8ost
View patch
redhatpatch availablevia redhat_api
Product: Red Hat OpenStack Platform 16.2Fixed in: python-flask-1:1.0.2-8.el8ost
View patch
redhatpatch availablevia redhat_api
Product: Red Hat OpenStack Platform 17.0Fixed in: python-flask-1:1.1.2-6.el9ost
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Quay 3Fixed in: quay/quay-rhel8:v3.10.0-150
View patch
redhatno patchvia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: python-flask
redhatno patchvia redhat_api
Product: Red Hat Storage 3Fixed in: python-flask

Vendor Advisories (2)

redhatCVE-2023-30861Important

flask: Possible disclosure of permanent session cookie due to missing Vary: Cookie header

May 5, 2023
pipGHSA-m2qf-hxjv-5gpqhigh

Flask vulnerable to possible disclosure of permanent session cookie due to missing Vary: Cookie header

May 1, 2023

References

github.com / pallets/flask/commit/70f906c51ce49c485f1d355703e9cc3386b1cc2b
Patch
github.com / pallets/flask/commit/afd63b16170b7c047f5758eb910c416511e9c965
Patch
github.com / pallets/flask/releases/tag/2.2.5
Release Notes
github.com / pallets/flask/releases/tag/2.3.2
Release Notes
github.com / pallets/flask/security/advisories/GHSA-m2qf-hxjv-5gpq
Vendor Advisory
lists.debian.org / debian-lts-announce/2023/08/msg00024.html
security.netapp.com / advisory/ntap-20230818-0006
debian.org / security/2023/dsa-5442