CVE-2026-55255

HIGH 8.4 KNOWN EXPLOITED PoC CATALOGUED ALL-YEARS

Published 2026-06-23 · Last modified 2026-10-07 · GitHub_M · NVD: Analyzed

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.

ACTIVELY EXPLOITED

Confirmed exploited in the wild — in CISA KEV since 2026-07-07. Patch or mitigate now.

Exploitation likelihood

0.9%chance of exploitation in 30 days · 59th percentile

● In CISA KEV (2026-07-07)● Catalogued PoC◆ SSVC: exploitation active, automatable no

Impact if exploited

8.4CVSS 3.1 · HIGH · CNA

ConfidentialityHigh
IntegrityHigh
AvailabilityLow

What an attacker needs

✓Access: Reachable over the network — no local access needed
⚠Privileges: Requires a low-privilege account
✓User interaction: No user interaction needed
⚠Complexity: Needs a race window or specific setup

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept

Public PoC or exploit resources are catalogued below.

VulnCheck KEV · XDB 84a4b14ed683 · Linked repository

Listed by the named source; Vulnpedia has not tested these resources.

PoC data: JSON

Resource commands

curl -s https://vulnpedia.com/cve/CVE-2026-55255/poc.jsonMachine-readable PoC index for this CVE (for automation).

Search for new PoCs

Search GitHub now — results may be empty or unverified.

Tracked sources are checked weekly for the full archive, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.

Data snapshot: 2026-10-26T06:59:15.268Z

Affected

Vendors Langflow Ai Langflow

Products Langflow

Weakness (CWE)

CWE-639: : Authorization Bypass Through User-Controlled Key

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L

References and research data (JSON)

Packages and version ranges

Each advisory describes its own package and affected ranges. A boundary applies to that range; it is not a universal upgrade recommendation.

langflow PyPI

pkg:pypi/langflow
ECOSYSTEM range
- All earlier versions (introduced 0)
- Fixed boundary (excluded): 1.9.1
294 explicitly listed affected versions
0.0.31, 0.0.32, 0.0.33, 0.0.40, 0.0.44, 0.0.45, 0.0.46, 0.0.52, 0.0.53, 0.0.54, 0.0.55, 0.0.56, 0.0.57, 0.0.58, 0.0.61, 0.0.62, 0.0.63, 0.0.64, 0.0.65, 0.0.66, 0.0.67, 0.0.68, 0.0.69, 0.0.70, 0.0.71, 0.0.72, 0.0.73, 0.0.74, 0.0.75, 0.0.76, 0.0.78, 0.0.79, 0.0.80, 0.0.81, 0.0.83, 0.0.84, 0.0.85, 0.0.86, 0.0.87, 0.0.88, 0.0.89, 0.1.0, 0.1.2, 0.1.3, 0.1.4, 0.1.5, 0.1.6, 0.1.7, 0.2.0, 0.2.1, 0.2.10, 0.2.11, 0.2.12, 0.2.13, 0.2.2, 0.2.3, 0.2.4, 0.2.5, 0.2.6, 0.2.7, 0.2.8, 0.2.9, 0.3.0, 0.3.1, 0.3.2, 0.3.3, 0.3.4, 0.4.0, 0.4.1, 0.4.10, 0.4.11, 0.4.12, 0.4.14, 0.4.15, 0.4.16, 0.4.17, 0.4.18, 0.4.19, 0.4.2, 0.4.20, 0.4.21, 0.4.3, 0.4.4, 0.4.5, 0.4.6, 0.4.7, 0.4.8, 0.4.9, 0.5.0, 0.5.0a0, 0.5.0a1, 0.5.0a2, 0.5.0a3, 0.5.0a4, 0.5.0a5, 0.5.0a6, 0.5.0b0, 0.5.0b2, 0.5.0b3, 0.5.0b4, 0.5.0b5, 0.5.0b6, 0.5.1, 0.5.10, 0.5.11, 0.5.12, 0.5.2, 0.5.3, 0.5.4, 0.5.5, 0.5.6, 0.5.7, 0.5.8, 0.5.9, 0.6.0, 0.6.0rc1, 0.6.1, 0.6.10, 0.6.11, 0.6.12, 0.6.14, 0.6.15, 0.6.16, 0.6.17, 0.6.18, 0.6.19, 0.6.2, 0.6.3, 0.6.3a0, 0.6.3a1, 0.6.3a2, 0.6.3a3, 0.6.3a4, 0.6.3a5, 0.6.3a6, 0.6.3a7, 0.6.4, 0.6.4a0, 0.6.4a1, 0.6.5, 0.6.5a0, 0.6.5a1, 0.6.5a10, 0.6.5a11, 0.6.5a12, 0.6.5a13, 0.6.5a2, 0.6.5a3, 0.6.5a4, 0.6.5a5, 0.6.5a6, 0.6.5a7, 0.6.5a8, 0.6.5a9, 0.6.6, 0.6.7, 0.6.7a1, 0.6.7a2, 0.6.7a3, 0.6.7a5, 0.6.8, 0.6.9, 1.0.0, 1.0.0a0, 1.0.0a1, 1.0.0a10, 1.0.0a11, 1.0.0a12, 1.0.0a13, 1.0.0a14, 1.0.0a15, 1.0.0a17, 1.0.0a18, 1.0.0a19, 1.0.0a2, 1.0.0a20, 1.0.0a21, 1.0.0a22, 1.0.0a23, 1.0.0a24, 1.0.0a25, 1.0.0a26, 1.0.0a27, 1.0.0a28, 1.0.0a29, 1.0.0a3, 1.0.0a30, 1.0.0a31, 1.0.0a32, 1.0.0a33, 1.0.0a34, 1.0.0a35, 1.0.0a36, 1.0.0a37, 1.0.0a38, 1.0.0a39, 1.0.0a4, 1.0.0a40, 1.0.0a41, 1.0.0a42, 1.0.0a43, 1.0.0a44, 1.0.0a45, 1.0.0a46, 1.0.0a47, 1.0.0a48, 1.0.0a49, 1.0.0a5, 1.0.0a50, 1.0.0a51, 1.0.0a52, 1.0.0a53, 1.0.0a55, 1.0.0a56, 1.0.0a57, 1.0.0a58, 1.0.0a59, 1.0.0a6, 1.0.0a60, 1.0.0a61, 1.0.0a7, 1.0.0a8, 1.0.0a9, 1.0.0rc0, 1.0.0rc1, 1.0.1, 1.0.10, 1.0.11, 1.0.12, 1.0.13, 1.0.14, 1.0.15, 1.0.16, 1.0.17, 1.0.18, 1.0.19, 1.0.19.post1, 1.0.19.post2, 1.0.2, 1.0.3, 1.0.4, 1.0.5, 1.0.6, 1.0.7, 1.0.8, 1.0.9, 1.1.0, 1.1.1, 1.1.2, 1.1.3, 1.1.4, 1.1.4.post1, 1.2.0, 1.3.0, 1.3.1, 1.3.2, 1.3.3, 1.3.4, 1.4.0, 1.4.1, 1.4.2, 1.4.3, 1.5.0, 1.5.0.post1, 1.5.0.post2, 1.5.1, 1.6.0, 1.6.1, 1.6.2, 1.6.3, 1.6.4, 1.6.5, 1.6.6, 1.6.7, 1.6.8, 1.6.9, 1.7.0, 1.7.1, 1.7.2, 1.7.3, 1.8.0, 1.8.0rc0, 1.8.0rc1, 1.8.0rc2, 1.8.0rc3, 1.8.0rc4, 1.8.0rc5, 1.8.0rc6, 1.8.1, 1.8.2, 1.8.3, 1.8.3rc0, 1.8.4, 1.9.0
Additional upstream package constraints
```
{
  "database": {
    "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-qrpv-q767-xqq2/GHSA-qrpv-q767-xqq2.json"
  }
}
```
GitHub Advisory Database · GHSA-qrpv-q767-xqq2 · Updated 2026-07-07T22:30:08.905598564Z
langflow PyPI

pkg:pypi/langflow
ECOSYSTEM range
- All earlier versions (introduced 0)
- Fixed boundary (excluded): 1.9.2
295 explicitly listed affected versions
0.0.31, 0.0.32, 0.0.33, 0.0.40, 0.0.44, 0.0.45, 0.0.46, 0.0.52, 0.0.53, 0.0.54, 0.0.55, 0.0.56, 0.0.57, 0.0.58, 0.0.61, 0.0.62, 0.0.63, 0.0.64, 0.0.65, 0.0.66, 0.0.67, 0.0.68, 0.0.69, 0.0.70, 0.0.71, 0.0.72, 0.0.73, 0.0.74, 0.0.75, 0.0.76, 0.0.78, 0.0.79, 0.0.80, 0.0.81, 0.0.83, 0.0.84, 0.0.85, 0.0.86, 0.0.87, 0.0.88, 0.0.89, 0.1.0, 0.1.2, 0.1.3, 0.1.4, 0.1.5, 0.1.6, 0.1.7, 0.2.0, 0.2.1, 0.2.10, 0.2.11, 0.2.12, 0.2.13, 0.2.2, 0.2.3, 0.2.4, 0.2.5, 0.2.6, 0.2.7, 0.2.8, 0.2.9, 0.3.0, 0.3.1, 0.3.2, 0.3.3, 0.3.4, 0.4.0, 0.4.1, 0.4.10, 0.4.11, 0.4.12, 0.4.14, 0.4.15, 0.4.16, 0.4.17, 0.4.18, 0.4.19, 0.4.2, 0.4.20, 0.4.21, 0.4.3, 0.4.4, 0.4.5, 0.4.6, 0.4.7, 0.4.8, 0.4.9, 0.5.0, 0.5.0a0, 0.5.0a1, 0.5.0a2, 0.5.0a3, 0.5.0a4, 0.5.0a5, 0.5.0a6, 0.5.0b0, 0.5.0b2, 0.5.0b3, 0.5.0b4, 0.5.0b5, 0.5.0b6, 0.5.1, 0.5.10, 0.5.11, 0.5.12, 0.5.2, 0.5.3, 0.5.4, 0.5.5, 0.5.6, 0.5.7, 0.5.8, 0.5.9, 0.6.0, 0.6.0rc1, 0.6.1, 0.6.10, 0.6.11, 0.6.12, 0.6.14, 0.6.15, 0.6.16, 0.6.17, 0.6.18, 0.6.19, 0.6.2, 0.6.3, 0.6.3a0, 0.6.3a1, 0.6.3a2, 0.6.3a3, 0.6.3a4, 0.6.3a5, 0.6.3a6, 0.6.3a7, 0.6.4, 0.6.4a0, 0.6.4a1, 0.6.5, 0.6.5a0, 0.6.5a1, 0.6.5a10, 0.6.5a11, 0.6.5a12, 0.6.5a13, 0.6.5a2, 0.6.5a3, 0.6.5a4, 0.6.5a5, 0.6.5a6, 0.6.5a7, 0.6.5a8, 0.6.5a9, 0.6.6, 0.6.7, 0.6.7a1, 0.6.7a2, 0.6.7a3, 0.6.7a5, 0.6.8, 0.6.9, 1.0.0, 1.0.0a0, 1.0.0a1, 1.0.0a10, 1.0.0a11, 1.0.0a12, 1.0.0a13, 1.0.0a14, 1.0.0a15, 1.0.0a17, 1.0.0a18, 1.0.0a19, 1.0.0a2, 1.0.0a20, 1.0.0a21, 1.0.0a22, 1.0.0a23, 1.0.0a24, 1.0.0a25, 1.0.0a26, 1.0.0a27, 1.0.0a28, 1.0.0a29, 1.0.0a3, 1.0.0a30, 1.0.0a31, 1.0.0a32, 1.0.0a33, 1.0.0a34, 1.0.0a35, 1.0.0a36, 1.0.0a37, 1.0.0a38, 1.0.0a39, 1.0.0a4, 1.0.0a40, 1.0.0a41, 1.0.0a42, 1.0.0a43, 1.0.0a44, 1.0.0a45, 1.0.0a46, 1.0.0a47, 1.0.0a48, 1.0.0a49, 1.0.0a5, 1.0.0a50, 1.0.0a51, 1.0.0a52, 1.0.0a53, 1.0.0a55, 1.0.0a56, 1.0.0a57, 1.0.0a58, 1.0.0a59, 1.0.0a6, 1.0.0a60, 1.0.0a61, 1.0.0a7, 1.0.0a8, 1.0.0a9, 1.0.0rc0, 1.0.0rc1, 1.0.1, 1.0.10, 1.0.11, 1.0.12, 1.0.13, 1.0.14, 1.0.15, 1.0.16, 1.0.17, 1.0.18, 1.0.19, 1.0.19.post1, 1.0.19.post2, 1.0.2, 1.0.3, 1.0.4, 1.0.5, 1.0.6, 1.0.7, 1.0.8, 1.0.9, 1.1.0, 1.1.1, 1.1.2, 1.1.3, 1.1.4, 1.1.4.post1, 1.2.0, 1.3.0, 1.3.1, 1.3.2, 1.3.3, 1.3.4, 1.4.0, 1.4.1, 1.4.2, 1.4.3, 1.5.0, 1.5.0.post1, 1.5.0.post2, 1.5.1, 1.6.0, 1.6.1, 1.6.2, 1.6.3, 1.6.4, 1.6.5, 1.6.6, 1.6.7, 1.6.8, 1.6.9, 1.7.0, 1.7.1, 1.7.2, 1.7.3, 1.8.0, 1.8.0rc0, 1.8.0rc1, 1.8.0rc2, 1.8.0rc3, 1.8.0rc4, 1.8.0rc5, 1.8.0rc6, 1.8.1, 1.8.2, 1.8.3, 1.8.3rc0, 1.8.4, 1.9.0, 1.9.1
Additional upstream package constraints
```
{
  "ecosystem": {},
  "database": {
    "source": "https://github.com/pypa/advisory-database/blob/main/vulns/langflow/PYSEC-2026-221.yaml"
  }
}
```
PyPA · PYSEC-2026-221 · Updated 2026-06-26T00:00:06.061343789Z

Unverified PoC candidates

Catalogue matches for further research. These repositories have not been validated as working exploits.

1 candidate

https://github.com/rootdirective-sec/CVE-2026-55255-LabPoC-in-GitHub · CVE-2026-55255
PoC-in-GitHub · CVE-2026-55255 · Updated 2026-06-30T14:52:54Z

Additional exploitation reports

Source-specific reports, separate from CISA KEV. Repeated observations from one source are not independent confirmations.

VulnCheck KEV · 2026-06-26T00:00:00Z
Source guidance: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
Source ransomware assessment: Unknown
VulnCheck KEV · CVE-2026-55255 · Updated 2026-06-26T00:00:00Z
VulnCheck KEV · 2026-06-26T00:00:00ZVulnCheck KEV · CVE-2026-55255
VulnCheck KEV · 2026-07-07T00:00:00ZVulnCheck KEV · CVE-2026-55255
VulnCheck KEV · CVE-2026-55255
VulnCheck KEV · 2026-07-29T00:00:00ZVulnCheck KEV · CVE-2026-55255
VulnCheck KEV · 2026-08-07T00:00:00ZVulnCheck KEV · CVE-2026-55255
VulnCheck KEV · 2026-08-20T00:00:00ZVulnCheck KEV · CVE-2026-55255
VulnCheck KEV · 2026-08-27T00:00:00ZVulnCheck KEV · CVE-2026-55255
VulnCheck KEV · 2026-08-28T00:00:00ZVulnCheck KEV · CVE-2026-55255

Known Affected Software Configurations

Vendor	Product	Version range
Langflow	Langflow	< 1.9.1

All CVSS metrics

HIGH 8.4 v3.1 · CNA Primary
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L
HIGH 8.4 v3.1 · NVD Secondary
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L

References

Exploit-tagged references (not proof of a PoC)

https://github.com/langflow-ai/langflow/security/advisories/GHSA-qrpv-q767-xqq2 x_refsource_CONFIRMexploitExploitMitigationVendor AdvisoryWEBEVIDENCECVE record · GitHub_M · Updated 2026-07-07T22:14:22.487Z
CVE record · CISA-ADP · Updated 2026-10-07T18:13:46.054Z
NVD · CVE-2026-55255 · Updated 2026-10-25T23:10:00.167
GitHub Advisory Database · GHSA-qrpv-q767-xqq2
PyPA · PYSEC-2026-221
GitHub Advisory Database · GHSA-qrpv-q767-xqq2 · Updated 2026-07-07T22:30:08.905598564Z

Patches & mitigations

https://github.com/langflow-ai/langflow/pull/12832 x_refsource_MISCIssue TrackingPatchWEBFIXCVE record · GitHub_M · Updated 2026-07-07T22:14:22.487Z
NVD · CVE-2026-55255 · Updated 2026-10-25T23:10:00.167
GitHub Advisory Database · GHSA-qrpv-q767-xqq2
PyPA · PYSEC-2026-221
GitHub Advisory Database · GHSA-qrpv-q767-xqq2 · Updated 2026-07-07T22:30:08.905598564Z
https://github.com/langflow-ai/langflow/commit/2c9f498d664a3c32698b57d7c5e752625291060e x_refsource_MISCPatchWEBCVE record · GitHub_M · Updated 2026-07-07T22:14:22.487Z
NVD · CVE-2026-55255 · Updated 2026-10-25T23:10:00.167
GitHub Advisory Database · GHSA-qrpv-q767-xqq2
GitHub Advisory Database · GHSA-qrpv-q767-xqq2 · Updated 2026-07-07T22:30:08.905598564Z

Advisories

https://webflow.sysdig.com/blog/understanding-langflow-cve-2026-55255-and-why-higher-cvss-vulnerabilities-arent-always-the-most-exploited third-party-advisoryThird Party AdvisoryWEBKEV reportCVE record · CISA-ADP · Updated 2026-10-07T18:13:46.054Z
NVD · CVE-2026-55255 · Updated 2026-10-25T23:10:00.167
GitHub Advisory Database · GHSA-qrpv-q767-xqq2
GitHub Advisory Database · GHSA-qrpv-q767-xqq2 · Updated 2026-07-07T22:30:08.905598564Z
VulnCheck KEV · CVE-2026-55255 · Updated 2026-06-26T00:00:00Z
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-55255 government-resourceUS Government ResourceWEBCVE record · CISA-ADP · Updated 2026-10-07T18:13:46.054Z
NVD · CVE-2026-55255 · Updated 2026-10-25T23:10:00.167
GitHub Advisory Database · GHSA-qrpv-q767-xqq2
GitHub Advisory Database · GHSA-qrpv-q767-xqq2 · Updated 2026-07-07T22:30:08.905598564Z
https://osv.dev/vulnerability/GHSA-qrpv-q767-xqq2 ADVISORYGitHub Advisory Database · GHSA-qrpv-q767-xqq2
GitHub Advisory Database · GHSA-qrpv-q767-xqq2 · Updated 2026-07-07T22:30:08.905598564Z
https://nvd.nist.gov/vuln/detail/CVE-2026-55255 ADVISORYGitHub Advisory Database · GHSA-qrpv-q767-xqq2
GitHub Advisory Database · GHSA-qrpv-q767-xqq2 · Updated 2026-07-07T22:30:08.905598564Z
https://osv.dev/vulnerability/PYSEC-2026-221 ADVISORYPyPA · PYSEC-2026-221
PyPA · PYSEC-2026-221 · Updated 2026-06-26T00:00:06.061343789Z
https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-38517 ADVISORYEUVD · EUVD-2026-38517
https://vulncheck.com/kev ADVISORYVulnCheck KEV · CVE-2026-55255 · Updated 2026-06-26T00:00:00Z

Technical & other

https://github.com/langflow-ai/langflow PACKAGEGitHub Advisory Database · GHSA-qrpv-q767-xqq2
GitHub Advisory Database · GHSA-qrpv-q767-xqq2 · Updated 2026-07-07T22:30:08.905598564Z
https://github.com/pypa/advisory-database/tree/main/vulns/langflow/PYSEC-2026-221.yaml WEBGitHub Advisory Database · GHSA-qrpv-q767-xqq2
GitHub Advisory Database · GHSA-qrpv-q767-xqq2 · Updated 2026-07-07T22:30:08.905598564Z
https://previdian.com/CVE-2026-55255 KEV reportVulnCheck KEV · CVE-2026-55255 · Updated 2026-06-26T00:00:00Z
https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json KEV reportVulnCheck KEV · CVE-2026-55255 · Updated 2026-06-26T00:00:00Z
https://www.resecurity.com/es/blog/article/exploiting-langflows-validatecode-endpoint-for-remote-code-execution KEV reportVulnCheck KEV · CVE-2026-55255 · Updated 2026-06-26T00:00:00Z
https://www.recordedfuture.com/blog/july-2026-cve-landscape KEV reportVulnCheck KEV · CVE-2026-55255 · Updated 2026-06-26T00:00:00Z
https://www.acn.gov.it/portale/documents/20119/1300791/Operational_Summary_lug26_CLEAR.pdf/88b05799-3e4c-f3ed-4a42-d9e68e080604?t=1787220905144 KEV reportVulnCheck KEV · CVE-2026-55255 · Updated 2026-06-26T00:00:00Z
https://expel.com/blog/the-ai-cve-exploitation-evidence-story-headlines-are-scarier-than-reality/ KEV reportVulnCheck KEV · CVE-2026-55255 · Updated 2026-06-26T00:00:00Z
https://www.vulncheck.com/blog/pwning-the-ai-stack KEV reportVulnCheck KEV · CVE-2026-55255 · Updated 2026-06-26T00:00:00Z
https://vulncheck.com/xdb/84a4b14ed683 XDB catalogueVulnCheck KEV · 84a4b14ed683 · Updated 2026-06-26T00:00:00Z
https://github.com/rootdirective-sec/CVE-2026-55255-Lab XDB repositoryVulnCheck KEV · 84a4b14ed683 · Updated 2026-06-26T00:00:00Z

Sources: NVD · CVE.org · All sources and attribution · EPSS