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Fencer Vulns
medium 6.5

CVE-2021-22959 json

The parser in accepts requests with a space (SP) right after the header name before the colon.

published 2021-11-15 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-10084

cvss
6.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.2%
EPSS 3.2% chance of exploitation in 30 days, percentile 88%
public exploits
0
none known

Summary

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.

Patch / fix

  • NodeJS Node 12.22.7, 14.18.1, 16.11.1
  • nodejs Debian 14, Debian 13, Debian 12 12.22.7~dfsg-1

debian advisories DEBIAN-CVE-2021-22959

  • npm RHEL 8 1:6.14.15-1.14.18.2.2.module+el8.5.0+13644+8d46dafd
  • nodejs RHEL 8 1:14.18.2-2.module+el8.5.0+13644+8d46dafd
  • nodejs-nodemon RHEL 8 2.0.15-1.module+el8.5.0+13504+a2e74d91
  • nodejs-full-i18n RHEL 8 1:14.18.2-2.module+el8.5.0+13644+8d46dafd
  • nodejs-packaging RHEL 8, RHEL 8.4 EUS 23-3.module+el8.3.0+6519+9f98ed83
  • npm RHEL 8 1:8.1.2-1.16.13.1.3.module+el8.5.0+13548+45d748af
  • nodejs RHEL 8 1:16.13.1-3.module+el8.5.0+13548+45d748af
  • nodejs-nodemon RHEL 8 2.0.15-1.module+el8.5.0+13548+45d748af

red hat advisories RHSA-2022:0350RHSA-2021:5171RHSA-2022:0246RHEA-2022:5139RHEA-2022:5221RHEA-2022:5615

  • nodejs10 SLES for SAP 15 SP2, SLES for SAP 15 SP1, SLES for SAP 15 +18 more 10.24.1-150000.1.47.1
  • nodejs12 SLE Module for Web and Scripting 12 12.22.9-1.38.1
  • nodejs14 SLE Module for Web and Scripting 15 SP3, SLE Module for Web and Scripting 15 SP2 14.18.1-15.21.2
  • nodejs12 SLE Module for Web and Scripting 15 SP3, SLE Module for Web and Scripting 15 SP2 12.22.7-4.22.1
  • nodejs14 SLE Module for Web and Scripting 12 14.18.1-6.18.2

suse advisories SUSE-SU-2022:2855-1SUSE-SU-2022:0101-1SUSE-SU-2021:3964-1SUSE-SU-2021:3940-1SUSE-SU-2021:3886-1

  • python-httptools openSUSE Tumbleweed 0.6.1-1.9
  • nodejs14 openSUSE Tumbleweed 14.18.1-1.1
  • nodejs16 openSUSE Tumbleweed 16.13.0-1.1
  • nodejs12 openSUSE Leap 15.2 12.22.7-lp152.3.21.1
  • nodejs14 openSUSE Leap 15.2 14.18.1-lp152.17.1
  • nodejs14 openSUSE Leap 15.3 14.18.1-15.21.2
  • nodejs12 openSUSE Leap 15.3 12.22.7-4.22.1

opensuse advisories openSUSE-SU-2025:15095-1openSUSE-SU-2024:11616-1openSUSE-SU-2024:11637-1openSUSE-SU-2021:1574-1openSUSE-SU-2021:1552-1openSUSE-SU-2021:3964-1

  • npm AlmaLinux 8 1:6.14.15-1.14.18.2.2.module_el8.5.0+2618+8d46dafd
  • npm AlmaLinux 8 1:6.14.15-1.14.18.2.2.module_el8.5.0+254+b4526b16
  • nodejs AlmaLinux 8 1:14.18.2-2.module_el8.5.0+2618+8d46dafd
  • nodejs AlmaLinux 8 1:14.18.2-2.module_el8.5.0+254+b4526b16
  • nodejs-nodemon AlmaLinux 8 2.0.15-1.module_el8.6.0+2904+f21ad6f4
  • nodejs-nodemon AlmaLinux 8 2.0.15-1.module_el8.5.0+2605+45d748af
  • nodejs-nodemon AlmaLinux 8 2.0.15-1.module_el8.5.0+2618+8d46dafd
  • nodejs-full-i18n AlmaLinux 8 1:14.18.2-2.module_el8.5.0+2618+8d46dafd

almalinux advisories ALSA-2022:0350ALSA-2021:5171

  • nodejs Rocky Linux 8 1:14.18.2-2.module+el8.5.0+733+de4fee6c
  • nodejs-nodemon Rocky Linux 8 2.0.15-1.module+el8.5.0+721+4c107270
  • nodejs-packaging Rocky Linux 8 23-3.module+el8.7.0+1071+4bdda2a8
  • nodejs-packaging Rocky Linux 8 23-3.module+el8.3.0+100+234774f7
  • nodejs-packaging Rocky Linux 8 23-3.module+el8.5.0+733+de4fee6c
  • nodejs Rocky Linux 8 1:16.13.1-3.module+el8.5.0+721+4c107270
  • nodejs-packaging Rocky Linux 8 25-1.module+el8.6.0+1046+80feca58
  • nodejs-packaging Rocky Linux 8 25-1.module+el8.5.0+702+221f14e6

rocky linux advisories RLSA-2022:0350RLSA-2021:5171

  • nodejs Alpine 3.12 12.22.10-r0
  • nodejs Alpine 3.24, Alpine 3.23, Alpine 3.22 +9 more 14.18.1-r0
  • nodejs-current Alpine 3.24, Alpine 3.23, Alpine 3.22 +8 more 16.11.1-r0

alpine advisories ALPINE-CVE-2021-22959

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • nodejs Arch Linux 16.11.1-1

arch linux advisories AVG-2460

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-22959 updated cvss 6.1

llhttp: HTTP Request Smuggling due to spaces in headers

  • Red Hat Quay 3 quay/quay-rhel8
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux AppStream (v. 8) nodejs 14.18.2-2.module+el8.5.0+13644+8d46dafd, nodejs 16.13.1-3.module+el8.5.0+13548+45d748af, nodejs 12.22.12-1.module+el8.6.0+15324+1f2c5d8d, nodejs-packaging 17-3.module+el8.1.0+3369+37ae6a45, nodejs-packaging 23-3.module+el8.3.0+6519+9f98ed83, nodejs-packaging 25-1.module+el8.5.0+10992+fac5fe06, +9 more
    fixed: vendor fix RHSA-2022:0350
  • Red Hat Enterprise Linux AppStream E4S (v. 8.1) nodejs 12.22.12-1.module+el8.1.0+15296+87b2f6ad, nodejs-packaging 17-3.module+el8.1.0+3369+37ae6a45, nodejs-nodemon 1.18.3-1.module+el8.1.0+3369+37ae6a45, npm 6.14.16-1.12.22.12.1.module+el8.1.0+15296+87b2f6ad, nodejs-full-i18n 12.22.12-1.module+el8.1.0+15296+87b2f6ad
    fixed: vendor fix RHEA-2022:4925
  • Red Hat Enterprise Linux AppStream EUS (v. 8.2) nodejs 12.22.12-1.module+el8.2.0+15322+a70ca0ab, nodejs-packaging 17-3.module+el8.1.0+3369+37ae6a45, nodejs-nodemon 1.18.3-1.module+el8.1.0+3369+37ae6a45, npm 6.14.16-1.12.22.12.1.module+el8.2.0+15322+a70ca0ab, nodejs-full-i18n 12.22.12-1.module+el8.2.0+15322+a70ca0ab
    fixed: vendor fix RHEA-2022:5221
  • Red Hat Enterprise Linux AppStream EUS (v.8.4) nodejs 14.18.2-2.module+el8.4.0+13643+6c0ebf22, nodejs 12.22.12-1.module+el8.4.0+15323+4d1cc445, nodejs-packaging 17-3.module+el8.1.0+3369+37ae6a45, nodejs-packaging 23-3.module+el8.3.0+6519+9f98ed83, nodejs-nodemon 2.0.3-1.module+el8.4.0+11732+c668cc9f, nodejs-nodemon 2.0.15-1.module+el8.4.0+13503+fc29810b, +4 more
    fixed: vendor fix RHEA-2022:5615
  • Red Hat Software Collections for RHEL Workstation(v. 7) rh-nodejs14-nodejs 14.18.2-1.el7, rh-nodejs12-nodejs 12.22.12-2.el7, rh-nodejs14-npm 6.14.15-14.18.2.1.el7, rh-nodejs12-npm 6.14.16-12.22.12.2.el7, rh-nodejs14-nodejs-nodemon 2.0.3-6.el7 Red Hat Software Collections for RHEL(v. 7) rh-nodejs14-nodejs 14.18.2-1.el7, rh-nodejs12-nodejs 12.22.12-2.el7, rh-nodejs14-npm 6.14.15-14.18.2.1.el7, rh-nodejs12-npm 6.14.16-12.22.12.2.el7, rh-nodejs14-nodejs-nodemon 2.0.3-6.el7
    fixed: vendor fix RHSA-2022:4914
  • Red Hat Enterprise Linux 9 npm, nodejs, nodejs-libs, nodejs-full-i18n
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

3.16% chance of exploitation in the next 30 days, higher than 88% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • hackerone.com https://hackerone.com/reports/1238709 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
NVD 2.0 6.4 AV:N/AC:L/Au:N/C:P/I:P/A:N

Affected products

  • NodeJS Node

Classification

Weakness
  • CWE-444 Inconsistent Interpretation of HTTP Requests
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.