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CVE-2022-51020 mher CVE debrief

CVE-2022-51020 is a cross-site request forgery vulnerability in Flower before version 2.2.0. The vulnerability is due to Tornado xsrf_cookies being disabled and the OAuth session cookie lacking SameSite. Attackers can lure authenticated users to malicious pages that POST to /api/worker/shutdown, /api/worker/pool/restart, or /api/task/revoke to shut down Celery workers, resize pools, and revoke tasks.

Vendor
mher
Product
flower
CVSS
MEDIUM 6
CISA KEV
Not listed in stored evidence
Original CVE published
2026-10-12
Original CVE updated
2026-10-12
Advisory published
2026-10-12
Advisory updated
2026-10-12

Who should care

Defenders responsible for Flower instances, especially those with authenticated users, should assess exposure and prioritize remediation. They should verify exposure of Flower instances, assess the feasibility of CSRF attacks, and upgrade to version 2.2.0 or later. Defenders should also monitor for suspicious activity on /api/worker/shutdown, /api/worker/pool/restart, and /api/task/revoke endpoints.

Why it matters

CVE-2022-51020 is a CSRF vulnerability in Flower before 2.2.0 that allows attackers to perform actions on behalf of authenticated users. Defenders should prioritize verifying exposure and remediation.

  • Potential shutdown of Celery workers
  • Possible resizing of pools by attackers
  • Revocation of tasks by attackers
  • Verification of Flower instance exposure and patching

Technical summary

The vulnerability is caused by Tornado xsrf_cookies being disabled and the OAuth session cookie lacking SameSite. This allows attackers to lure authenticated users to malicious pages that POST to /api/worker/shutdown, /api/worker/pool/restart, or /api/task/revoke. Defenders should prioritize verifying exposure of Flower instances, especially those with authenticated users, and assess the feasibility of CSRF attacks. Remediation involves upgrading to version 2.2.0 or later. The vulnerability allows attackers to shut down Celery workers, resize pools, and revoke tasks.

Defensive priority

Defenders should prioritize verifying exposure of Flower instances, especially those with authenticated users, and assess the feasibility of CSRF attacks. Remediation involves upgrading to version 2.2.0 or later.

Recommended defensive actions

  • Verify Flower instance exposure, especially those with authenticated users
  • Assess the feasibility of CSRF attacks
  • Upgrade to version 2.2.0 or later
  • Monitor for suspicious activity on /api/worker/shutdown, /api/worker/pool/restart, and /api/task/revoke endpoints
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record and source item provide details on the vulnerability, including affected versions and patch commits. However, there is limited information on exploitation or victim impact. Defenders should verify exposure of Flower instances, especially those with authenticated users, and assess the feasibility of CSRF attacks. The vulnerability is caused by Tornado xsrf_cookies being disabled and the OAuth session cookie lacking SameSite. This allows attackers to lure authenticated users to malicious pages that POST to /api/worker/sh

Sources and references

Verified primary and authoritative sources

  • CVE-2022-51020 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2022-51020

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2022-51020 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2022-51020

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Flower before 2.2.0 CSRF via Worker and Task Control API Endpoints

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2022/51xxx/CVE-2022-51020.json

    cve_program_cvelist_v5

  • Source reference

    Unverified legacy reference

    URL: https://github.com/mher/flower/issues/1217

    Supplemental source - issue-tracking

  • Source reference

    Unverified legacy reference

    URL: https://github.com/mher/flower/commit/a14408b16cc3d2877d36659005ce0d72b6162629

    Supplemental source - patch

  • Source reference

    Unverified legacy reference

    URL: https://github.com/mher/flower/commit/3b2115af7f9c42bd2da2fbcbd919f77013e9ec51

    Supplemental source - patch

  • Source reference

    Unverified legacy reference

    URL: https://github.com/mher/flower/blob/v2.1.0/flower/api/control.py

    Supplemental source - technical-description

  • Source reference

    Unverified legacy reference

    URL: https://github.com/mher/flower

    Supplemental source - product

  • Source reference

    Unverified legacy reference

    URL: https://www.vulncheck.com/advisories/flower-before-2.2.0-csrf-via-worker-and-task-control-api-endpoints

    Supplemental source - third-party-advisory

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.