How severe is CVE-2026-23835?

No CVSS score has been assigned to CVE-2026-23835 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-23835?

CVE-2026-23835 affects the following packages: @lobehub/chat (npm). Ecosystems affected: npm.

How do I fix CVE-2026-23835?

Update @lobehub/chat to 1.143.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-23835 is resolved across your whole dependency graph.

How do I detect CVE-2026-23835 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @lobehub/chat, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-23835 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2026-23835?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-23835 can be triaged on real exposure rather than presence alone.

Is CVE-2026-23835 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-23835 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-23835?

CVE-2026-23835 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 29th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-23835?

CVE-2026-23835 is classified as CWE-73 (CWE-73). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-23835 published, and has it been updated?

CVE-2026-23835 was published on January 30, 2026 and was last updated on August 12, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

Not in CISA KEV

CVE-2026-23835 — @lobehub/chat

Fix: lobehub/lobehub@2c1762b

CVE-2026-23835 is a CWE-73 vulnerability in @lobehub/chat. A fix is available for @lobehub/chat — see the affected versions and patch details below.

LobeHub Vulnerable to Improper Authorization in Presigned Upload

Also known asGHSA-wrrr-8jcv-wjf5

Published

Jan 30, 2026

Updated

Aug 12, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Sep 22, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-23835.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs29th percentile — riskier than 29% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

0other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

@lobehub/chatnpm

13Kdownloads / week

Description

Summary

The file upload feature in Knowledge Base > File Upload does not validate the integrity of the upload request, allowing users to intercept and modify the request parameters. As a result, it is possible to create arbitrary files in abnormal or unintended paths. In addition, since lobechat.com relies on the size parameter from the request to calculate file usage, an attacker can manipulate this value to misrepresent the actual file size, such as uploading a 1 GB file while reporting it as 10 MB, or falsely declaring a 10 MB file as a 1 GB file.

Details

After entering the Knowledge Base, click the file upload option and upload any file. At this point, use a tool such as Burp Suite to intercept and inspect the request sent to POST /trpc/lambda/file.createFile?batch=1 (the request packet is shown in the image below). By modifying the name and size fields in this request, it is possible to bypass the maximum upload size enforced by LobeChat’s monthly subscription plan and upload files beyond the intended service storage limits. <img width="670" height="413" alt="image" src="https://github.com/user-attachments/assets/c83cfb81-3bcc-4562-b052-5344ccf6356f" />

Impacts

By manipulating the size value provided in the client upload request, it is possible to bypass the monthly upload quota enforced by the server and continuously upload files beyond the intended storage and traffic limits. This abuse can result in a discrepancy between actual resource consumption and billing calculations, causing direct financial impact to the service operator. Additionally, exhaustion of storage or related resources may lead to degraded service availability, including failed uploads, delayed content delivery, or temporary suspension of upload functionality for legitimate users. A single malicious user can also negatively affect other users or projects sharing the same subscription plan, effectively causing an indirect denial of service (DoS). Furthermore, excessive and unaccounted-for uploads can distort monitoring metrics and overload downstream systems such as backup processes, malware scanning, and media processing pipelines, ultimately undermining overall operational stability and service reliability

PoC

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`@lobehub/chat`	all versions	1.143.3`npm install @lobehub/chat@1.143.3`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @lobehub/chat, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @lobehub/chat to 1.143.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-23835 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-23835 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2026-23835. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Summary The file upload feature in `Knowledge Base > File Upload` does not validate the integrity of the upload request, allowing users to intercept and modify the request parameters. As a result, it is possible to create arbitrary files in abnormal or unintended paths. In addition, since `lobechat.com` relies on the size parameter from the request to calculate file usage, an attacker can manipulate this value to misrepresent the actual file size, such as uploading a `1 GB` file while reporting it as `10 MB`, or falsely declaring a `10 MB` file as a `1 GB` file. ### Details After entering

O3 Security · Impact-Aware SCA

Is CVE-2026-23835 in your dependencies?

O3 Security finds CVE-2026-23835 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

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