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CVE-2023-0040

24
FAUCET Score

CVE-2023-0040 is a CRLF injection vulnerability affecting Async HTTP Client versions prior to 1.13.2. It allows attackers to inject new HTTP header fields or entirely new requests into the data stream by manipulating unsanitized input in HTTP header field values. With a CVSS score of 7.5 (HIGH), this vulnerability has a network attack vector, low attack complexity, and can lead to significant logical errors and misbehaviors, though data disclosure is unlikely. There is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
< 1.4.1CPE matchmatch criteria
cpe:2.3:a:asynchttpclient_project:async-http-client:*:*:*:*:*:*:*:*
>= 1.5.0, < 1.9.1CPE matchmatch criteria
cpe:2.3:a:asynchttpclient_project:async-http-client:*:*:*:*:*:*:*:*
>= 1.10.0, < 1.12.1CPE matchmatch criteria
cpe:2.3:a:asynchttpclient_project:async-http-client:*:*:*:*:*:*:*:*
>= 1.13.0, < 1.13.2CPE matchmatch criteria
cpe:2.3:a:asynchttpclient_project:async-http-client:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
HIGH
Availability Impact
NONE
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.55%
Probability of exploitation in next 30 days
EPSS Percentile
42.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
This CVE's current EPSS score of 0.0055 is in the 20th percentile among its peer group of 51,485 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (6)

djangopatch availablevia llm_extracted
Fixed in: 1.13.2
falcopatch availablevia llm_extracted
Fixed in: 1.13.2
swiftpatch availablevia ghsa
Product: github.com/swift-server/async-http-clientFixed in: 1.13.2
swiftpatch availablevia ghsa
Product: github.com/swift-server/async-http-clientFixed in: 1.12.1
swiftpatch availablevia ghsa
Product: github.com/swift-server/async-http-clientFixed in: 1.9.1
swiftpatch availablevia ghsa
Product: github.com/swift-server/async-http-clientFixed in: 1.4.1

Vendor Advisories (3)

swiftGHSA-v3r5-pjpm-mwgqhigh

Async HTTP Client has CRLF Injection vulnerability in HTTP request headers

Jun 7, 2023
falcollm-falco-328a7182d7170c01

CRLF injection in Async HTTP Client prior to 1.13.2.

djangollm-django-702fe9bf7d077595

CVE-2023-0040

References

github.com / swift-server/async-http-client/security/advisories/GHSA-v3r5-pjpm-mwgq
Third Party Advisory