# CVE-2026-85181: Dianping CAT session cookie forgery via weak hash integrity check

Source: https://junglewise.ai/threats/cve-2026-85181-dianping-cat-session-cookie-forgery-via-weak-hash-integrity-check  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-03. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-85181 · Severity: critical · CVSS 9.8 · Published 2026-09-03

Dianping CAT is a performance monitoring and diagnostics platform deeply integrated into Meituan's infrastructure. The platform uses a weak cryptographic hash (Java String.hashCode) to verify session cookies, allowing attackers to forge valid admin sessions offline and gain full configuration access without needing valid credentials or the server's secret key.

Technologies: [Dianping CAT](https://junglewise.ai/threats/technologies/cat). Vendors: [Dianping](https://junglewise.ai/threats/vendors/dianping).

## Quick answers

**Is CVE-2026-85181 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-85181 being exploited in the wild.

**How severe is CVE-2026-85181?** Critical severity, with a CVSS score of 9.8, published 3 September 2026.

**Which products and versions are affected?** Dianping CAT 3.1.0 and earlier.

**Is there a fix for CVE-2026-85181?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-85181 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-85181?** Check whether you run Dianping CAT at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is a cryptographic weakness in session token integrity verification. CAT's TokenBuilder class uses Java's String.hashCode as the sole integrity check for session cookies, without employing a server-side key or HMAC-based approach. This allows an attacker to compute valid cookie checksums offline through brute force. Additionally, the platform's IP binding validation can be bypassed by setting the x-forwarded-for header, enabling attackers to forge admin sessions with complete configuration access. The attack requires no authentication or special network access—only the ability to send HTTP requests. Fix availability depends on Meituan releasing a patched version using proper cryptographic signatures (e.g., HMAC-SHA256 with a server-side key).

## Affected products

- Dianping CAT 3.1.0 and earlier

## Timeline

- 2026-09-03: disclosed

## References

- [https://github.com/dianping/cat](https://github.com/dianping/cat)
- [https://github.com/dianping/cat/blob/3.1.0/cat-home/src/main/java/com/dianping/cat/system/page/login/service/TokenBuilder.java](https://github.com/dianping/cat/blob/3.1.0/cat-home/src/main/java/com/dianping/cat/system/page/login/service/TokenBuilder.java)

## Related threats

- [Dianping CAT cross-site scripting in report handler](https://junglewise.ai/threats/cve-2026-124506-a-vulnerability-has-been-found-in-dianping-cat-3-0-0-3-1-0-4-0)
- [Dianping CAT open redirect in login handler](https://junglewise.ai/threats/cve-2026-124505-a-flaw-has-been-found-in-dianping-cat-3-0-0-3-1-0-4-0-rc1-this)