CVE-2021-22959

Exp

The parser in accepts requests with a space (SP) right after the header name before the colon. This can lead to HTTP Request Smuggling (HRS) in llhttp < v2.1.4 and < v6.0.6.

Published: 2021-11-15 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-22959 is rated Exploit Available (56/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.21%). 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-2021-22959

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

Exploit prediction scoring system (EPSS) score for CVE-2021-22959

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 2025-11-21 0.48% 0.21% -0.27%
2 2025-11-18 0.21% 0.48% +0.28%
3 2025-03-30 — 0.21% —

Full EPSS history (16 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-22959

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N 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:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 2.5 [email protected]
6.4 2.0 MEDIUM
AV:N/AC:L/Au:N/C:P/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 10.0 4.9 [email protected]

Weakness enumeration for CVE-2021-22959

OS Trackers for CVE-2021-22959

vendor priority summary link
alpine medium CVE-2021-22959: 2 source package rows (nodejs, nodejs-current); 15 state rows across 15 repos (3.12-main, 3.17-community, 3.17-main, 3.18-community, 3.18-main, 3.19-community, 3.19-main, 3.20-community, 3.20-main, 3.21-community, 3.21-main, 3.22-community, 3.22-main, edge-community, edge-main); fixed 15, open 0. https://security.alpinelinux.org/vuln/CVE-2021-22959
debian not yet assigned CVE-2021-22959 not yet assigned priority: Debian including 1 source packages (nodejs), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-22959
gentoo low CVE-2021-22959: 1 GLSA(s) (202405-29), 1 atom(s) (net-libs/nodejs); latest impact low. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2021-22959
redhat low — https://access.redhat.com/security/cve/CVE-2021-22959
suse medium CVE-2021-22959 severity moderate: SUSE including 60 source package names (12-10.1:nodejs12-12.22.7-4.22.1, 12-10.1:npm12-12.22.7-4.22.1, …), 208 product×package rows across 35 product lines (Container bci/nodejs, SUSE CaaS Platform 4.0, … (35 product lines)): Fixed 200, Known Not Affected 8. https://www.suse.com/security/cve/CVE-2021-22959/
ubuntu medium CVE-2021-22959 medium priority: Ubuntu including 1 source packages (nodejs), 11 status rows across 11 suites (bionic, focal, hirsute, impish, jammy, kinetic, lunar, mantic, trusty, upstream, xenial): not-affected 7, ignored 3, released 1. https://ubuntu.com/security/CVE-2021-22959

Affected software / configurations for CVE-2021-22959

Vendor Product Version Raw CPE
llhttp llhttp < 2.1.4 cpe:2.3:a:llhttp:llhttp:*:*:*:*:*:node.js:*:*
llhttp llhttp >= 3.0.0, < 6.0.6 cpe:2.3:a:llhttp:llhttp:*:*:*:*:*:node.js:*:*
oracle graalvm 20.3.4 cpe:2.3:a:oracle:graalvm:20.3.4:*:*:*:enterprise:*:*:*
oracle graalvm 21.3.0 cpe:2.3:a:oracle:graalvm:21.3.0:*:*:*:enterprise:*:*:*
debian debian_linux 11.0 cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

References for CVE-2021-22959

URL Tags
https://hackerone.com/reports/1238709 Exploit Issue Tracking Third Party Advisory
https://www.debian.org/security/2022/dsa-5170 Mailing List Third Party Advisory
https://www.oracle.com/security-alerts/cpujan2022.html Patch Third Party Advisory
cvelogic Threat Intelligence