CVE-2021-33026
9.8
CRITICAL · CVSS 3.1 · EPSS 7.1% (pctl 94)
In your normal cycle
Critical by CVSS (9.8), but no sign of active exploitation.
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
Scoring
| CVSS | 9.8 (CRITICAL, v3.1) |
|---|---|
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| EPSS | 7.06% — more likely to be exploited than 94% of all CVEs |
| Weakness | CWE-502 |
| On CISA KEV | no |
| Public exploit | none known |
| Published | 2021-05-13 |
| Last modified | 2026-06-17 |
Affected (1)
| Vendor | Product |
|---|---|
| flask-caching project | flask-caching |
References
→ the Explorer · watch your stack · NVD