CVE-2026-55255

CRITICALPre-NVD 8.49.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2026-07-07), indicating real-world exploitation has been confirmed by US federal agencies. A secondary CVSS source baseline 8.4 retained for reference (NVD's own analysis pending). Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, epss, secondary
Exploited in the wild
9.0EG
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS PROB: 0.9%CVSS: 8.4Exploit: cisa kev · ssvc activeExposed services: Not assessed

A fix is available — apply it.

Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.1, an Insecure Direct Object Reference (IDOR) vulnerability in /api/v1/responses endpoint allows an authenticated attacker to execute any flow belonging to another user by specifying the victim's flow ID in the request. This vulnerability is fixed in 1.9.1.

CVSS v3
8.4
EG Score
9.0CRITICALhigh confidence
EG Risk
81
EG Risk 81/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity90% × 45%
Exploitation100% × 40%
Automatability0% × 15%
CISA SSVC: Track at low, Attend at medium and Act at high mission impact.
Action: A fix is available. Apply it within your standard update timelines at low, sooner than that at medium and as soon as possible at high mission impact.
EPSS PROB
0.9%
EPSS %ILE
58th
KEV
⚠ Exploited

CISA SSVCTrack at low, Attend at medium and Act at high mission impact.

A fix is available. Apply it within your standard update timelines at low, sooner than that at medium and as soon as possible at high mission impact.

Exploitation active (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

June 19, 2026

Last Modified

October 7, 2026

Advisory Details (2)

Auto-updated Jul 4, 2026
🔬 Proof of concept available. Patch available. Sources: github_pr, github.
githubMentions a patch (unverified)🟡 PoC Available

IDOR Vulnerability in `/api/v1/responses` Endpoint Allows Authenticated Attackers to Access Another User's Flow · Advisory · langflow-ai/langflow · GitHub

https://github.com/langflow-ai/langflow/security/advisories/GHSA-qrpv-q767-xqq2
github_pr

fix(security): close IDOR in get_flow_by_id_or_endpoint_name (LE-639)

Fix merged in langflow-ai/langflow PR #12832 on 2026-04-22 — awaiting tagged release

https://github.com/langflow-ai/langflow/pull/12832

Vendor Advisories for CVE-2026-55255(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFix by version rangeDependents
langflow0.0.31 ... 1.9.1 (295 versions)
  • every version up to 1.9.1: fixed in 1.9.1
  • every version up to 1.9.2: fixed in 1.9.2
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 14× in last 7d / 68× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 235 total refreshes for this CVE.

  1. 2026-10-10 22:06 UTCEG score recompute
  2. 2026-10-10 20:00 UTCEPSS rescore
  3. 2026-10-09 23:40 UTCEG score recompute
  4. 2026-10-09 20:07 UTCEPSS rescore
  5. 2026-10-08 17:48 UTCEG score recompute
  6. 2026-10-08 17:12 UTCEPSS rescore
  7. 2026-10-08 02:47 UTCEG score recompute
  8. 2026-10-07 23:48 UTCEPSS rescore
  9. 2026-10-07 19:19 UTCEG score recompute
  10. 2026-10-07 18:27 UTCEG score recompute
  11. 2026-10-06 17:21 UTCEG score recompute
  12. 2026-10-06 15:18 UTCEPSS rescore
  13. 2026-10-05 18:50 UTCEG score recompute
  14. 2026-10-05 17:43 UTCEPSS rescore
  15. 2026-10-03 18:11 UTCEG score recompute
  16. 2026-10-03 14:26 UTCEPSS rescore
  17. 2026-10-02 19:44 UTCEG score recompute
  18. 2026-10-02 17:56 UTCEPSS rescore
  19. 2026-10-01 21:20 UTCEG score recompute
  20. 2026-10-01 19:50 UTCEPSS rescore
  21. 2026-09-30 15:29 UTCEG score recompute
  22. 2026-09-30 15:03 UTCEPSS rescore
  23. 2026-09-29 17:08 UTCEG score recompute
  24. 2026-09-29 15:22 UTCEPSS rescore
  25. 2026-09-28 22:29 UTCEG score recompute
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  1. 2026-09-28 15:02 UTCEG score recompute
  2. 2026-09-28 13:51 UTCEPSS rescore
  3. 2026-09-27 21:51 UTCCISA KEV update
  4. 2026-09-27 16:38 UTCEG score recompute
  5. 2026-09-27 13:48 UTCEPSS rescore
  6. 2026-09-26 18:14 UTCEG score recompute
  7. 2026-09-26 15:59 UTCEPSS rescore
  8. 2026-09-26 03:17 UTCEG score recompute
  9. 2026-09-25 19:35 UTCCISA KEV update
  10. 2026-09-25 14:55 UTCCISA KEV update
  11. 2026-09-24 19:31 UTCCISA KEV update
  12. 2026-09-24 17:40 UTCEG score recompute
  13. 2026-09-24 14:04 UTCEPSS rescore
  14. 2026-09-23 19:18 UTCEG score recompute
  15. 2026-09-23 17:54 UTCEPSS rescore
  16. 2026-09-22 19:36 UTCCISA KEV update
  17. 2026-09-22 17:12 UTCEG score recompute
  18. 2026-09-21 22:32 UTCEG score recompute
  19. 2026-09-21 19:09 UTCCISA KEV update
  20. 2026-09-20 20:26 UTCEG score recompute
  21. 2026-09-20 20:16 UTCEPSS rescore
  22. 2026-09-19 18:18 UTCEG score recompute
  23. 2026-09-18 19:55 UTCEG score recompute
  24. 2026-09-18 19:28 UTCEPSS rescore
  25. 2026-09-18 19:20 UTCCISA KEV update
  26. 2026-09-18 14:15 UTCCISA KEV update
  27. 2026-09-17 21:31 UTCEG score recompute
  28. 2026-09-17 19:31 UTCEPSS rescore
  29. 2026-09-16 15:36 UTCEG score recompute
  30. 2026-09-16 14:10 UTCCISA KEV update
  31. 2026-09-16 14:08 UTCEPSS rescore
  32. 2026-09-16 08:09 UTCEG score recompute
  33. 2026-09-16 05:15 UTCEPSS rescore
  34. 2026-09-15 06:02 UTCEG score recompute
  35. 2026-09-15 03:11 UTCEPSS rescore
  36. 2026-09-14 19:24 UTCCISA KEV update
  37. 2026-09-13 20:26 UTCEG score recompute
  38. 2026-09-13 16:47 UTCEPSS rescore
  39. 2026-09-12 18:22 UTCEG score recompute
  40. 2026-09-11 18:49 UTCCISA KEV update
  41. 2026-09-11 16:15 UTCEG score recompute
  42. 2026-09-11 14:53 UTCEPSS rescore
  43. 2026-09-11 12:31 UTCEG score recompute
  44. 2026-09-10 19:28 UTCCISA KEV update
  45. 2026-09-10 10:22 UTCEG score recompute
  46. 2026-09-10 09:35 UTCEPSS rescore
  47. 2026-09-09 19:08 UTCCISA KEV update
  48. 2026-09-09 00:45 UTCEG score recompute
  49. 2026-09-08 22:01 UTCEPSS rescore
  50. 2026-09-08 18:54 UTCCISA KEV update
  51. 2026-09-07 18:49 UTCEG score recompute
  52. 2026-09-07 16:01 UTCEPSS rescore
  53. 2026-09-06 16:42 UTCEG score recompute
  54. 2026-09-06 13:47 UTCEPSS rescore
  55. 2026-09-05 18:18 UTCEG score recompute
  56. 2026-09-04 17:38 UTCCISA KEV update
  57. 2026-09-04 16:12 UTCEG score recompute
  58. 2026-09-04 08:44 UTCEG score recompute
  59. 2026-09-04 05:06 UTCEPSS rescore
  60. 2026-09-02 17:33 UTCCISA KEV update
  61. 2026-09-02 15:39 UTCEG score recompute
  62. 2026-09-02 14:12 UTCEPSS rescore
  63. 2026-09-01 17:13 UTCEG score recompute
  64. 2026-09-01 13:54 UTCEPSS rescore
  65. 2026-09-01 05:59 UTCEG score recompute
  66. 2026-09-01 04:40 UTCEPSS rescore
  67. 2026-08-31 14:19 UTCCISA KEV update
  68. 2026-08-30 20:19 UTCEG score recompute
  69. 2026-08-30 19:17 UTCEPSS rescore
  70. 2026-08-30 01:37 UTCEG score recompute
  71. 2026-08-30 01:22 UTCEPSS rescore
  72. 2026-08-28 23:28 UTCEG score recompute
  73. 2026-08-28 21:41 UTCEPSS rescore
  74. 2026-08-27 17:34 UTCEG score recompute
  75. 2026-08-27 17:22 UTCCISA KEV update

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Frequently asked(6)

What is CVE-2026-55255?
CVE-2026-55255 is a critical vulnerability published on June 19, 2026. Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.1, an Insecure Direct Object Reference (IDOR) vulnerability in /api/v1/responses endpoint allows an authenticated attacker to execute any flow belonging to another user by specifying the victim's flow ID in…
When was CVE-2026-55255 disclosed?
CVE-2026-55255 was first published on June 19, 2026, with the most recent update on October 7, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55255 actively exploited?
Yes. CISA added CVE-2026-55255 to the Known Exploited Vulnerabilities catalog on July 7, 2026, affecting Langflow Langflow. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate attention. A fix is available. Apply it.
What is the CVSS score of CVE-2026-55255?
CVE-2026-55255 has a CVSS base score of 8.4 (a secondary CVSS source that NVD displays; NVD's own analysis pending). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0 (CRITICAL).
Which products are affected by CVE-2026-55255?
CVE-2026-55255 affects Langflow Langflow. The affected packages EchelonGraph has on record, with version ranges, are listed in the Affected Packages section of this page.
How do I remediate CVE-2026-55255?
A fix for CVE-2026-55255 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-55255 are linked in the Vendor Advisories panel on this page.

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