Couchauth: Improper Neutralization of Special Elements in Output Used by a Downstream Component
CVE-2023-39655 is a critical-severity improper neutralization of special elements in output used by a downstream component vulnerability in Couchauth from Perfood, with a CVSS 3.1 base score of 9.6 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. Affected Couchauth versions: 0.20.0 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 0.53% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of Couchauth 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.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
Version data comes from NVD's product matching. 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
- RequiredA user must take an action such as opening a file or link.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- 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:R/S:C/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 9.6 | Critical | NVD |
| CVSS 3.1 | 9.6 | Critical | CISA (ADP) |
Official description
A host header injection vulnerability exists in the NPM package @perfood/couch-auth versions <= 0.20.0. By sending a specially crafted host header in the forgot password request, it is possible to send password reset links to users which, once clicked, lead to an attacker-controlled server and thus leak the password reset token. This may allow an attacker to reset other users' passwords and take over their accounts.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of Special Elements in Output Used by a Downstream Component
The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.
How developers prevent this class of flaw
- Programming languages and supporting technologies might be chosen which are not subject to these issues.
- Utilize an appropriate mix of allowlist and denylist parsing to filter control-plane syntax from all input.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- github.com/dub-flow/vulnerability-research/tree/main/CVE-2023-39655Third Party Advisory
Other references
Recent Improper Neutralization of Special Elements in Output Used by a Downstream Component vulnerabilities
- 9.8 Critical severity
- 7.2 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
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