Security readout for executives and security teams
Plain-English summary
Flask-Caching through 1.10.1 uses Python Pickle to serialize cached data. If an attacker can write to the cache store, they may poison cached content so Python code runs when the app reads it. Business impact is severe, but the cited note says practical exploitation is unlikely without prior cache or host access.
Executive priority
Treat as a high-priority exposure review for Flask applications, especially internet-facing services with Redis, Memcached, or filesystem cache backends. Urgency rises sharply if cache infrastructure may be exposed or compromised.
Technical view
This is CWE-502 unsafe deserialization in Flask-Caching through 1.10.1. The issue depends on attacker control of cache storage such as filesystem, Memcached, or Redis, followed by cache poisoning. The CVE rates impact as critical, but the source notes exploitation needs write access and a required collision, limiting real-world reach.
Likely exposure
Exposure is most likely in Flask applications using Flask-Caching through 1.10.1 where cache storage is shared, exposed, weakly isolated, or writable after host or service compromise.
Exploitation context
CISA KEV status is false in the supplied bundle. The CVE text supports possible RCE or local privilege escalation, but also states exploitation is extremely unlikely unless the machine is already compromised or cache writes are possible.
Researcher notes
The key question is not only package version; it is whether an attacker can write to cache storage and trigger unsafe deserialization. Sources do not provide confirmed exploitation, a named fixed version, or complete affected-product metadata.
Mitigation direction
- Inventory Flask apps using Flask-Caching through 1.10.1.
- Review project guidance and PR 209 before choosing remediation.
- Restrict filesystem, Memcached, Redis, and other cache backends from untrusted writes.
- Clear or rebuild cache data after suspected unauthorized cache access.
- Harden cache credentials, network exposure, and service isolation.
Validation and detection
- Check dependency manifests and lockfiles for Flask-Caching versions.
- Map each application to its configured cache backend.
- Verify untrusted users or services cannot write cache entries.
- Review cache, Redis, Memcached, and host logs for unauthorized access.
- Confirm remediation in staging before clearing production caches.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-502: Code execution behavior lookup
Code execution and unsafe deserialization weaknesses often justify reviewing execution behavior and process telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupPrivilege behavior lookup
The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-33026 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/sh4nks/flask-caching/pull/209CVE reference · x_refsource_MISC
- https://github.com/pallets-eco/flask-caching/pull/209#issuecomment-1136397937CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Deserialization of Untrusted Data
Deserialization of Untrusted Data represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.