libuv: Server-Side Request Forgery
CVE-2024-24806 is a high-severity server-side request forgery vulnerability in libuv, with a CVSS 3.1 base score of 7.3 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected libuv versions: >= 1.45.0, < 1.48.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 2% chance of exploitation within 30 days, higher than 81% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of libuv you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
- 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
- LowSome restricted data can be read.
- Integrity
- LowLimited modification of data is possible.
- Availability
- LowPerformance or availability is reduced.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.3 | High | CNA (github.com) |
| CVSS 3.1 | 7.3 | High | NVD |
Official description
libuv is a multi-platform support library with a focus on asynchronous I/O. The `uv_getaddrinfo` function in `src/unix/getaddrinfo.c` (and its windows counterpart `src/win/getaddrinfo.c`), truncates hostnames to 256 characters before calling `getaddrinfo`. This behavior can be exploited to create addresses like `0x00007f000001`, which are considered valid by `getaddrinfo` and could allow an attacker to craft payloads that resolve to unintended IP addresses, bypassing developer checks. The vulnerability arises due to how the `hostname_ascii` variable (with a length of 256 bytes) is handled in `uv_getaddrinfo` and subsequently in `uv__idna_toascii`. When the hostname exceeds 256 characters, it gets truncated without a terminating null byte. As a result attackers may be able to access internal APIs or for websites (similar to MySpace) that allows users to have `username.example.com` pages. Internal services that crawl or cache these user pages can be exposed to SSRF attacks if a malicious user chooses a long vulnerable username. This issue has been addressed in release version 1.48.0. Users are advised to upgrade. There are no known workarounds for this vulnerability.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Server-Side Request Forgery
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.
How developers prevent this class of flaw
- If there is a known list of applications, IP, hostname, and/or domains to which the product is allowed to communicate, then use allowlists to ensure that outgoing requests are restricted to these known entities. The allowlists could be in the application code or possibly enforced by firewalls or network segmentation.
- If the product is expected to be able to connect to arbitrary IP addresses or domains, consider using a denylist that includes private network addresses, internal domain names, etc. The denylist could be in the application code or possibly enforced by firewalls or network segmentation.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Patches and release notes
Third-party and government advisories
- openwall.com/lists/oss-security/2024/02/08/2Mailing List, Third Party Advisory
- openwall.com/lists/oss-security/2024/02/11/1Mailing List, Third Party Advisory
Other references
Recent Server-Side Request Forgery vulnerabilities
- 8.2 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 9.8 Critical severity
- 9.8 Critical severity
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