langbot-app LangBot up to 4.8.6 cross site scripting

CVSS Meta Temp Score
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CTI Interest Score
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5.0$0-$5k0.00

Summaryinfo

A vulnerability classified as problematic has been found in langbot-app LangBot up to 4.8.6. The affected element is an unknown function. The manipulation leads to cross site scripting. This vulnerability is referenced as CVE-2026-28509. Remote exploitation of the attack is possible. No exploit is available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in langbot-app LangBot up to 4.8.6. This issue affects some unknown processing. The manipulation with an unknown input leads to a cross site scripting vulnerability. Using CWE to declare the problem leads to CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Impacted is integrity. The summary by CVE is:

LangBot is a global IM bot platform designed for LLMs. Prior to version 4.8.7, LangBot’s web UI renders user-supplied raw HTML using rehypeRaw, which can lead to a cross-site scripting (XSS) vulnerability. This issue has been patched in version 4.8.7.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-28509 since 02/27/2026. The exploitation is known to be easy. The attack may be initiated remotely. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1059.007 according to MITRE ATT&CK.

Upgrading to version 4.8.7 eliminates this vulnerability. Applying the patch 614621ab7b84fe50da3c6137705cde5a99429866 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-9985). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.1
VulDB Meta Temp Score: 5.0

VulDB Base Score: 3.5
VulDB Temp Score: 3.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 5.4
NVD Vector: 🔒

CNA Base Score: 6.3
CNA Vector (GitHub_M): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Cross site scripting
CWE: CWE-79 / CWE-94 / CWE-74
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: LangBot 4.8.7
Patch: 614621ab7b84fe50da3c6137705cde5a99429866

Timelineinfo

02/27/2026 CVE reserved
03/06/2026 +7 days Advisory disclosed
03/06/2026 +0 days VulDB entry created
03/16/2026 +10 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: GHSA-w8gq-g4pc-xh3h
Status: Confirmed

CVE: CVE-2026-28509 (🔒)
GCVE (CVE): GCVE-0-2026-28509
GCVE (VulDB): GCVE-100-349355
EUVD: 🔒

Entryinfo

Created: 03/06/2026 07:37
Updated: 03/16/2026 17:28
Changes: 03/06/2026 07:37 (66), 03/06/2026 13:30 (1), 03/16/2026 17:28 (12)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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