High

SSRF in Chainlit SQLAlchemy persistence deployments

IdentifiersCVE-2026-21219CWE-918

CVE-2026-21219 is a server-side request forgery (SSRF) vulnerability in Chainlit that affects deployments using SQLAlchemy for data persistence. According to the provided content, the issue is triggered when an attacker supplies a custom element containing a URL that the Chainlit server fetches on the attacker's behalf, allowing access to resources the attacker could not directly reach. The content also notes that this flaw can be combined with other issues to map internal services and access sensitive cloud metadata endpoints.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows an attacker to coerce the Chainlit server into making arbitrary outbound requests to attacker-specified URLs reachable from the server environment. This can expose internal network services, cloud metadata endpoints, and other restricted resources. In the scenario described, AWS EC2 deployments with IMDSv1 enabled may allow retrieval of instance metadata, including credentials and role endpoint information, which could lead to cloud account compromise, lateral movement, data theft, and source code theft. The content also states the vulnerability may be chained with other flaws to amplify impact.

Mitigation

If you can’t patch tonight, do this now.

Where immediate patching is not possible, reduce SSRF exposure by restricting outbound network access from the Chainlit server, blocking access to link-local and internal address spaces, and preventing server-side fetches of untrusted user-supplied URLs where feasible. For AWS EC2 deployments, enable IMDSv2 and disable or restrict IMDSv1 access, as the provided content states the described metadata-access path does not apply when IMDSv2 is enabled.

Remediation

Patch, then assume compromise.

Upgrade Chainlit to version 2.9.4, which the provided content identifies as the release that fixes CVE-2026-21219 and the related disclosed vulnerability.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

Microsoft Corporation.Windows Sdkapplication

Microsoft CorporationWindows Software Development Kitapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

2 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

2 SOURCESView more in app

dark readingNews

Jan 20, 2026

Vulnerabilities Threaten to Break Chainlit AI Framework

An SSRF vulnerability in Chainlit (notably when using SQLAlchemy persistence) that allows an attacker to coerce the server into fetching attacker-supplied URLs, potentially reaching internal resources such as AWS EC2 Instance Metadata Service v1 (IMDSv1) to steal cloud credentials.

What this page doesn’t show

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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity1

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES

MITRE CVE

cve.org · CVE-2026-21219

NVD

nvd.nist.gov/vuln/detail/CVE-2026-21219

MITRE CWE · CWE-918

cwe.mitre.org

Vendor Advisory

msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21219