CVE-2023-22465 | Http4s has fatal error parsing User-Agent and Server headers

Exp

Http4s is a Scala interface for HTTP services. Starting with version 0.1.0 and prior to versions 0.21.34, 0.22.15, 0.23.17, and 1.0.0-M38, the `User-Agent` and `Server` header parsers are susceptible to a fatal error on certain inputs. In http4s, modeled headers are lazily parsed, so this only applies to services that explicitly request these typed headers. Fixes are released in 0.21.34, 0.22.15, 0.23.17, and 1.0.0-M38. As a workaround, use the weakly typed header interface.

Published: 2023-01-04 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-22465 is rated High Exploit Risk (64.1/100): CVSS High severity, with medium exploitation likelihood (EPSS 0.84%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2023-22465

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2023-22465

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.34% 0.84% +0.51%
2 2026-01-07 0.43% 0.34% -0.10%
3 2026-01-05 — 0.43% —

Full EPSS history (8 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-22465

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 3.9 1.4 [email protected]

Weakness enumeration for CVE-2023-22465

GitHub Security Advisory for CVE-2023-22465

GHSA-54w6-vxfh-fw7f · Severity: high · Ecosystem: maven — Http4s improperly parses User-Agent and Server headers

Affected software / configurations for CVE-2023-22465

Vendor Product Version Raw CPE
typelevel http4s >= 0.1.0, < 0.21.34 cpe:2.3:a:typelevel:http4s:*:*:*:*:*:*:*:*
typelevel http4s >= 0.22.0, < 0.22.15 cpe:2.3:a:typelevel:http4s:*:*:*:*:*:*:*:*
typelevel http4s >= 0.23.0, < 0.23.17 cpe:2.3:a:typelevel:http4s:*:*:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone1:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone10:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone11:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone12:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone13:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone14:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone15:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone16:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone17:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone18:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone19:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone2:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone20:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone21:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone22:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone23:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone24:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone25:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone26:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone27:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone28:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone29:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone3:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone30:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone31:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone32:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone33:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone34:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone35:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone36:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone37:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone4:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone5:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone6:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone7:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone8:*:*:*:*:*:*
typelevel http4s 1.0.0 cpe:2.3:a:typelevel:http4s:1.0.0:milestone9:*:*:*:*:*:*

References for CVE-2023-22465

URL Tags
https://github.com/http4s/http4s/security/advisories/GHSA-54w6-vxfh-fw7f Exploit Mitigation Third Party Advisory
cvelogic Threat Intelligence