CVE-2021-33026
The Flask-Caching extension through 1.10.1 for Flask relies on Pickle for serialization, which may lead to remote code execution or local privilege escalation.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (7.01%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
The Flask-Caching extension through 1.10.1 for Flask relies on Pickle for serialization, which may lead to remote code execution or local privilege escalation. If an attacker gains access to cache storage (e.g., filesystem, Memcached, Redis, etc.), they can construct a crafted payload, poison the cache, and execute Python code. NOTE: a third party indicates that exploitation is extremely unlikely unless the machine is already compromised; in other cases, the attacker would be unable to write their payload to the cache and generate the required collision
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 7.01% probability · 94th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-502
- Affected
- flask-caching project/flask-caching
- Source
- cve@mitre.org
References
- https://github.com/pallets-eco/flask-caching/pull/209#issuecomment-1136397937Issue Tracking, Patch, Third Party Advisory
- https://github.com/sh4nks/flask-caching/pull/209Patch, Third Party Advisory
- https://github.com/pallets-eco/flask-caching/pull/209#issuecomment-1136397937Issue Tracking, Patch, Third Party Advisory
- https://github.com/sh4nks/flask-caching/pull/209Patch, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.