cat: Reliance on Cookies without Validation and Integrity Checking
CVE-2026-85181 is a critical-severity reliance on cookies without validation and integrity checking vulnerability in cat from Dianping, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected cat versions: 3.1.0 and earlier. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.7% chance of exploitation within 30 days, higher than 54% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of cat you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (vulncheck.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 9.3 | Critical | CNA (vulncheck.com) |
| CVSS 3.1 | 9.8 | Critical | CNA (vulncheck.com) |
Official description
CAT uses Java String.hashCode as the sole integrity check for session cookies without server-side keying, allowing attackers to forge valid checksums offline. Attackers can set the x-forwarded-for header to bypass IP binding validation and create admin sessions with full configuration access.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Reliance on Cookies without Validation and Integrity Checking
The product relies on the existence or values of cookies when performing security-critical operations, but it does not properly ensure that the setting is valid for the associated user.
How developers prevent this class of flaw
- Avoid using cookie data for a security-related decision.
- Perform thorough input validation (i.e.: server side validation) on the cookie data if you're going to use it for a security related decision.
- Add integrity checks to detect tampering.
More Reliance on Cookies without Validation and Integrity Checking vulnerabilities (CWE-565)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
- github.com/dianping/cat
- github.com/dianping/cat/blob/3.1.0/cat-home/src/main/java/com/dianping/cat/system/page/login/service/TokenBui…
- github.com/dianping/cat/blob/3.1.0/cat-home/src/main/java/com/dianping/cat/util/HttpUtils.java
- github.com/dianping/cat/issues/2384
- vulncheck.com/advisories/cat-through-3.1.0-session-cookie-forgery-via-unkeyed-hashcode-checksum
Recent Reliance on Cookies without Validation and Integrity Checking vulnerabilities
- 8.3 High severity
- 8.1 High severity
- 9.1 Critical severity
- 8.8 High severity
- 9.8 Critical severity
- 9.8 Critical severity
Spotted an error? Tell us.