CVE-2021-33026
highpriority · attend · 52EPSS 0.073 · 94 %ileexploit · PoCDEEURUUSEPSS · scored 2026-10-27
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
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–critical · 4.2–9.8
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
exploits (2)
Public proof-of-concept and weaponised exploit code.
affected products (12)
Products and version ranges known to be affected.
- IBM Maximo Asset Management 7.6.1.2all versionscert_bundDEcpe:/a:ibm:maximo_asset_management:7.6.1.2
- IBM Maximo Asset Management 7.6.1.3all versionscert_bundDEcpe:/a:ibm:maximo_asset_management:7.6.1.3
- flask-caching project flask-caching≤ 1.10.1nvdUScpe:2.3:a:flask-caching_project:flask-caching:*:*:*:*:*:*:*:*
advisories (2)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2023-0426IBM Spectrum Protect: Mehrere SchwachstellenDeutsch2022-03-13csaf · cert_bundDE
Ein entfernter, anonymer, authentisierter oder lokaler Angreifer kann mehrere Schwachstellen in IBM Spectrum Protect ausnutzen, um einen 'Denial of Service'-Zustand herbeizuführen, Sicherheitsmaßnahmen zu umgehen, einen 'Cross-Site-Scripting'-Angriff durchzuführen, beliebigen Code auszuführen, sensible Informationen offenzulegen und seine Privilegien zu erweitern.
- GHSA-656c-6cxf-hvcvDeserialization of Untrusted Data in Flask-Caching2021-06-18ghsa · osvUS
Flask-Cache adds easy cache support to Flask. 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. However, this is not a high-severity issue, as for an attack like this to work, an attacker must: 1. Be able to write arbitrary values to the cache 2. Be able to generate a cache key that will collide with a value being read by the application 3. Cause the application to read a maliciously-injected value Any situation where all 3 of those is true is a situation where the application has larger problems; for example, if someone's able to inject malicious cached rendered pages into a Flask app's cache, then they can make the website say literally anything they want, regardless of whether it involves the execution of remote code. Basically, the Pickle vulnerability follows from a website already being extremely vulnerable (due to conditions 1 and 2 being met).
also known as (5)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (7)
External citations — patches, advisories, analysis.
- https://github.com/pallets-eco/flask-caching/pull/209#issuecomment-1136397937cnnvd
- https://github.com/sh4nks/flask-caching/pull/209cnnvd
- https://vigilance.fr/vulnerability/Flask-Caching-code-execution-via-Serialization-37784cnnvd
- https://github.com/pallets-eco/flask-caching/pull/209#issuecomment-1136397937enisa_euvd
- https://github.com/sh4nks/flask-caching/pull/209enisa_euvd
- https://github.com/pallets-eco/flask-caching/pull/209#issuecomment-1136397937Issue TrackingPatchThird Party Advisorynvd
- https://github.com/sh4nks/flask-caching/pull/209PatchThird Party Advisorynvd
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