CVE-2023-0040
HIGHDescription
Versions of Async HTTP Client prior to 1.13.2 are vulnerable to a form of targeted request manipulation called CRLF injection. This vulnerability was the result of insufficient validation of HTTP header field values before sending them to the network. Users are vulnerable if they pass untrusted data into HTTP header field values without prior sanitisation. Common use-cases here might be to place usernames from a database into HTTP header fields. This vulnerability allows attackers to inject new HTTP header fields, or entirely new requests, into the data stream. This can cause requests to be understood very differently by the remote server than was intended. In general, this is unlikely to result in data disclosure, but it can result in a number of logical errors and other misbehaviours.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Exploit Intelligence
Moderate risk: more likely to be exploited than 43% of all known CVEs.
References
Related Vulnerabilities
Other CWE-93 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2025-61884 | High | 7.5 | 98% | KEV + Ransom | - |
| CVE-2022-0666 | High | 7.5 | 44% | - | Fix |
| CVE-2016-3115 | Medium | 6.4 | 37% | - | Fix |
| CVE-2024-20337 | High | 8.2 | 30% | - | Fix |
| CVE-2021-39172 | High | 8.8 | 29% | - | Fix |
| CVE-2016-4975 | Medium | 6.1 | 20% | - | Fix |
Common questions
How do I fix CVE-2023-0040?
Upgrade async-http-client to 1.13.2 or later.
Is CVE-2023-0040 being actively exploited?
Not that we know of. CVE-2023-0040 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.55% is the estimated probability that it will be exploited in the next 30 days. That is higher than 43% of all scored CVEs.
How severe is CVE-2023-0040?
CVE-2023-0040 has a CVSS v3 base score of 7.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2023-0040 affect?
Published advisories record a fix for async-http-client (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-04-03.