CVE
AppFlowy-IO AppFlowy-Cloud stored XSS in blob upload handling
- Exploited
- No known exploitation
- Fix
- No fix listed
- Who is exposed
- Not reported
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- FIRST's estimate of the chance attackers exploit it in the next 30 days, updated daily.What do these mean? →
- 0.19% · 8th percentile
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 13/100 · provisional
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
AppFlowy Cloud through 0.9.64 contains a stored cross-site scripting vulnerability that allows authenticated workspace members to upload blobs with unvalidated Content-Type values that are later served inline without a Content-Disposition header or authentication on the retrieval route. Attackers can upload a text/html or image/svg+xml blob via put_blob_handler, which is then rendered as an active same-origin document through the unauthenticated get_blob_handler endpoint and cached immutably for one year, enabling persistent script execution against any visitor who accesses the URL.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure3/25Reachable over the network · Unknown: No advisory context yet
- Reach?/20Unknown. No tracked technology or package matched
- Severity5.1/10CVSS 5.1
- No patch5/5No patch listed yet
What would change the score
- Would score about 68 if added to CISA KEV
- Would score about 63 if CISA's SSVC rates exploitation active
- Would score about 32 if advisories confirm default setups are exposed
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-127203 (AppFlowy Cloud 0.9.64 Stored XSS via Blob Upload Content-Type), using the cve.now data below.
Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.
What cve.now has for CVE-2026-127203 (entry last updated 2026-11-12):
Affected:
- AppFlowy-IO AppFlowy-Cloud: through 0.9.64
Fixed versions: none listed yet.
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
CISA KEV: CVE-2026-127203 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-127203 only. If you also check another CVE, look up its own KEV status; never assume it from this one.
How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.
Verify against the linked advisories before concluding, and cite the date you read each one:
- https://www.vulncheck.com/advisories/appflowy-cloud-stored-xss-via-blob-upload-content-type
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.
Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.
Entry: https://cve.now/CVE-2026-127203
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-127203"}.Timeline
- CVE published
- First seen by cve.now
Affected versions
- AppFlowy-IO AppFlowy-Cloud
through 0.9.64
Evidence 4
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Public exploit code · 1
Establishes: Public exploit code exists (Exploit-DB, Metasploit, Nuclei and GitHub).
- Exploit
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-127203
Is CVE-2026-127203 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-127203?
AppFlowy-Cloud: through 0.9.64.Source: cve.now feed data