CVE-2021-23017: f5 nginx Off-by-one Error

CVSS: 7.7v3.1HighModified

AliasesALPINE-CVE-2021-23017MGASA-2021-0301SUSE-SU-2021:1792-1+17 more

Published 01-06-2021Last modified 03-08-2024

Vulnerability summary

CVE-2021-23017 is a high (CVSS 7.7) Off-by-one Error vulnerability in f5 nginx. EPSS estimates a 53.46% chance of exploitation in the next 30 days, higher than 98.9% of scored vulnerabilities. 1 public exploit is recorded.

Overall risk

51/100

0100

High · default modelHow is this calculated?

CVSS score

7.7/10

010

High · v3.1 (NVD)

EPSS score

53.46%

0%100%

Critical · 0.00 pp in 30 days

KEVNot listedIn no KEV catalog

RansomwareNone recordedNo known use recorded

Public exploits1exploit-database

Advisory lineage

Upstream 0 · Downstream 1 · Related 1

OPENSUSE-SU-2024:11092-1

Timeline

01-06-2021
PublishedVulnerability first disclosed.
03-08-2024
Last modifiedVulnerability information updated.

Description

A security issue in nginx resolver was identified, which might allow an attacker who is able to forge UDP packets from the DNS server to cause 1-byte memory overwrite, resulting in worker process crash or potential other impact.

CVSS metrics

6 scores · 5 sources · 2 versions

v3.17.7v2.06.8

EPSS trend

Probability

53.46%

Chance of exploitation in the next 30 days

Percentile

99%

Versus all other CVEs

30-day change

0.00 pp

From 53.46% on 18-09-2026

18-09-202618-10-2026

EPSS score

53.46%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

1 found

exploit-databaseremotemultipleUnverified
Nginx 1.20.0 - Denial of Service (DOS)
Maturity: poc

Weaknesses

CWE · root cause

CWE-193Off-by-one ErrorA product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value.

Affected systems

Redhat34 products

automation-hub< 0:4.2.5-1.el7pc | < 0:4.2.5-1.el8pc
nginx< 1:1.18.0-3.module+el8.4.0+11152+f736ed63.1 | < 1:1.16.1-1.module+el8.1.0+11153+6c3a40a9.1 | < 1:1.16.1-1.module+el8.2.0+11154+636e4c3b.1 | < 1:1.16.1-2.module+el8.4.0+11155+68135136.1 | < 1:1.20.1-1.module+el8.5.0+13723+ab304644
nginx-all-modules< 1:1.18.0-3.module+el8.4.0+11152+f736ed63.1 | < 1:1.16.1-1.module+el8.1.0+11153+6c3a40a9.1 | < 1:1.16.1-1.module+el8.2.0+11154+636e4c3b.1 | < 1:1.16.1-2.module+el8.4.0+11155+68135136.1 | < 1:1.20.1-1.module+el8.5.0+13723+ab304644
nginx-debuginfo< 1:1.18.0-3.module+el8.4.0+11152+f736ed63.1 | < 1:1.16.1-1.module+el8.1.0+11153+6c3a40a9.1 | < 1:1.16.1-1.module+el8.2.0+11154+636e4c3b.1 | < 1:1.16.1-2.module+el8.4.0+11155+68135136.1 | < 1:1.20.1-1.module+el8.5.0+13723+ab304644
nginx-debugsource< 1:1.18.0-3.module+el8.4.0+11152+f736ed63.1 | < 1:1.16.1-1.module+el8.1.0+11153+6c3a40a9.1 | < 1:1.16.1-1.module+el8.2.0+11154+636e4c3b.1 | < 1:1.16.1-2.module+el8.4.0+11155+68135136.1 | < 1:1.20.1-1.module+el8.5.0+13723+ab304644

nginx-filesystem< 1:1.18.0-3.module+el8.4.0+11152+f736ed63.1 | < 1:1.16.1-1.module+el8.1.0+11153+6c3a40a9.1 | < 1:1.16.1-1.module+el8.2.0+11154+636e4c3b.1 | < 1:1.16.1-2.module+el8.4.0+11155+68135136.1 | < 1:1.20.1-1.module+el8.5.0+13723+ab304644
nginx-mod-http-image-filter< 1:1.18.0-3.module+el8.4.0+11152+f736ed63.1 | < 1:1.16.1-1.module+el8.1.0+11153+6c3a40a9.1 | < 1:1.16.1-1.module+el8.2.0+11154+636e4c3b.1 | < 1:1.16.1-2.module+el8.4.0+11155+68135136.1 | < 1:1.20.1-1.module+el8.5.0+13723+ab304644
nginx-mod-http-image-filter-debuginfo< 1:1.18.0-3.module+el8.4.0+11152+f736ed63.1 | < 1:1.16.1-1.module+el8.1.0+11153+6c3a40a9.1 | < 1:1.16.1-1.module+el8.2.0+11154+636e4c3b.1 | < 1:1.16.1-2.module+el8.4.0+11155+68135136.1 | < 1:1.20.1-1.module+el8.5.0+13723+ab304644
nginx-mod-http-perl< 1:1.18.0-3.module+el8.4.0+11152+f736ed63.1 | < 1:1.16.1-1.module+el8.1.0+11153+6c3a40a9.1 | < 1:1.16.1-1.module+el8.2.0+11154+636e4c3b.1 | < 1:1.16.1-2.module+el8.4.0+11155+68135136.1 | < 1:1.20.1-1.module+el8.5.0+13723+ab304644
nginx-mod-http-perl-debuginfo< 1:1.18.0-3.module+el8.4.0+11152+f736ed63.1 | < 1:1.16.1-1.module+el8.1.0+11153+6c3a40a9.1 | < 1:1.16.1-1.module+el8.2.0+11154+636e4c3b.1 | < 1:1.16.1-2.module+el8.4.0+11155+68135136.1 | < 1:1.20.1-1.module+el8.5.0+13723+ab304644
nginx-mod-http-xslt-filter< 1:1.18.0-3.module+el8.4.0+11152+f736ed63.1 | < 1:1.16.1-1.module+el8.1.0+11153+6c3a40a9.1 | < 1:1.16.1-1.module+el8.2.0+11154+636e4c3b.1 | < 1:1.16.1-2.module+el8.4.0+11155+68135136.1 | < 1:1.20.1-1.module+el8.5.0+13723+ab304644
nginx-mod-http-xslt-filter-debuginfo< 1:1.18.0-3.module+el8.4.0+11152+f736ed63.1 | < 1:1.16.1-1.module+el8.1.0+11153+6c3a40a9.1 | < 1:1.16.1-1.module+el8.2.0+11154+636e4c3b.1 | < 1:1.16.1-2.module+el8.4.0+11155+68135136.1 | < 1:1.20.1-1.module+el8.5.0+13723+ab304644
nginx-mod-mail< 1:1.18.0-3.module+el8.4.0+11152+f736ed63.1 | < 1:1.16.1-1.module+el8.1.0+11153+6c3a40a9.1 | < 1:1.16.1-1.module+el8.2.0+11154+636e4c3b.1 | < 1:1.16.1-2.module+el8.4.0+11155+68135136.1 | < 1:1.20.1-1.module+el8.5.0+13723+ab304644
nginx-mod-mail-debuginfo< 1:1.18.0-3.module+el8.4.0+11152+f736ed63.1 | < 1:1.16.1-1.module+el8.1.0+11153+6c3a40a9.1 | < 1:1.16.1-1.module+el8.2.0+11154+636e4c3b.1 | < 1:1.16.1-2.module+el8.4.0+11155+68135136.1 | < 1:1.20.1-1.module+el8.5.0+13723+ab304644
nginx-mod-stream< 1:1.18.0-3.module+el8.4.0+11152+f736ed63.1 | < 1:1.16.1-1.module+el8.1.0+11153+6c3a40a9.1 | < 1:1.16.1-1.module+el8.2.0+11154+636e4c3b.1 | < 1:1.16.1-2.module+el8.4.0+11155+68135136.1 | < 1:1.20.1-1.module+el8.5.0+13723+ab304644
nginx-mod-stream-debuginfo< 1:1.18.0-3.module+el8.4.0+11152+f736ed63.1 | < 1:1.16.1-1.module+el8.1.0+11153+6c3a40a9.1 | < 1:1.16.1-1.module+el8.2.0+11154+636e4c3b.1 | < 1:1.16.1-2.module+el8.4.0+11155+68135136.1 | < 1:1.20.1-1.module+el8.5.0+13723+ab304644
python-galaxy-ng< 0:4.2.5-2.el7pc | < 0:4.2.5-2.el8pc
python-pulpcore< 0:3.7.6-1.el7pc | < 0:3.7.6-1.el8pc
python3-galaxy-ng< 0:4.2.5-2.el7pc | < 0:4.2.5-2.el8pc
python3-pulpcore< 0:3.7.6-1.el7pc | < 0:3.7.6-1.el8pc
rh-nginx116-nginx< 1:1.16.1-6.el7
rh-nginx116-nginx-debuginfo< 1:1.16.1-6.el7
rh-nginx116-nginx-mod-http-image-filter< 1:1.16.1-6.el7
rh-nginx116-nginx-mod-http-perl< 1:1.16.1-6.el7
rh-nginx116-nginx-mod-http-xslt-filter< 1:1.16.1-6.el7
rh-nginx116-nginx-mod-mail< 1:1.16.1-6.el7
rh-nginx116-nginx-mod-stream< 1:1.16.1-6.el7
rh-nginx118-nginx< 1:1.18.0-3.el7
rh-nginx118-nginx-debuginfo< 1:1.18.0-3.el7
rh-nginx118-nginx-mod-http-image-filter< 1:1.18.0-3.el7
rh-nginx118-nginx-mod-http-perl< 1:1.18.0-3.el7
rh-nginx118-nginx-mod-http-xslt-filter< 1:1.18.0-3.el7
rh-nginx118-nginx-mod-mail< 1:1.18.0-3.el7
rh-nginx118-nginx-mod-stream< 1:1.18.0-3.el7

Show all 34

Suse15 products

nginx&distro=SUSE Enterprise Storage 6< 1.16.1-6.13.1
nginx&distro=SUSE Linux Enterprise High Performance Computing 15 SP1-ESPOS< 1.16.1-6.13.1
nginx&distro=SUSE Linux Enterprise High Performance Computing 15 SP1-LTSS< 1.16.1-6.13.1
nginx&distro=SUSE Linux Enterprise High Performance Computing 15-ESPOS< 1.16.1-3.15.1
nginx&distro=SUSE Linux Enterprise High Performance Computing 15-LTSS< 1.16.1-3.15.1

Show all 15

Oracle9 products

blockchain_platform< 21.1.2
communications_control_plane_monitor3.4 | 4.2 | 4.3 | 4.4
communications_fraud_monitor≥ 3.4, ≤ 4.4
communications_operations_monitor3.4 | 4.2 | 4.3 | 4.4
communications_session_border_controller8.4 | 9.0

Show all 9

Mageia2 products

nginx< 1.16.1-1.3.mga7
nginx< 1.18.0-5.1.mga8

Opensuse2 products

nginx&distro=openSUSE Leap 15.2< 1.16.1-lp152.2.3.1
nginx&distro=openSUSE Leap 15.3< 1.19.8-3.3.1

Alpine1 product

nginx≥ 0.6.18, < 1.16.1-r3 | ≥ 0.6.18, < 1.16.1-r7 | ≥ 0.6.18, < 1.18.0-r2 | ≥ 0.6.18, < 1.18.0-r14 | ≥ 0.6.18, < 1.20.1-r0

Debian1 product

nginx< 1.18.0-6.1 | < 1.14.2-2+deb10u4 | < 1.10.3-1+deb9u6

F51 product

nginx≥ 0.6.18, < 1.20.1

Fedoraproject1 product

fedoraEOL33 | 34

Netapp1 product

ontap_select_deploy_administration_utilityna

Openresty1 product

openresty< 1.19.3.2

Ubuntu1 product

nginx< 1.14.0-0ubuntu1.9 | < 1.18.0-0ubuntu1.2 | < 1.4.6-1ubuntu3.9+esm2 | < 1.10.3-0ubuntu0.16.04.5+esm1

12 vendors · 69 products

References

50 links

support.f5.com/csp/article/K12331123%2CX Refsource MISC
mailman.nginx.org/pipermail/nginx-announce/2021/000300.htmlX Refsource MISCMailing ListPatchVendor Advisory
lists.apache.org/thread.html/…Mailing ListX Refsource MLIST
lists.apache.org/thread.html/…Mailing ListX Refsource MLIST
lists.apache.org/thread.html/…Mailing ListX Refsource MLIST
lists.apache.org/thread.html/…Mailing ListX Refsource MLIST
lists.apache.org/thread.html/…Mailing ListX Refsource MLIST
lists.fedoraproject.org/archives/…Vendor AdvisoryX Refsource FEDORA
lists.fedoraproject.org/archives/…Vendor AdvisoryX Refsource FEDORA
www.oracle.com/security-alerts/cpuoct2021.htmlX Refsource MISCPatchThird Party Advisory

Show all 50 references

security.netapp.com/advisory/ntap-20210708-0006/X Refsource CONFIRMThird Party Advisory
www.oracle.com/security-alerts/cpujan2022.htmlX Refsource MISCPatchThird Party Advisory
www.oracle.com/security-alerts/cpuapr2022.htmlX Refsource MISCPatchThird Party Advisory
packetstormsecurity.com/files/167720/Nginx-1.20.0-Denial-Of-Service.htmlX Refsource MISCThird Party AdvisoryVDB Entry
security.alpinelinux.org/vuln/CVE-2021-23017Advisory
advisories.mageia.org/MGASA-2021-0301.htmlAdvisory
bugs.mageia.org/show_bug.cgi?id=28965REPORT
www.openwall.com/lists/oss-security/2021/05/25/5WEB
lists.fedoraproject.org/archives/…WEB
www.suse.com/support/update/announcement/2021/suse-su-20211792-1/Advisory
bugzilla.suse.com/1186126REPORT
www.suse.com/security/cve/CVE-2021-23017WEB
www.suse.com/support/update/announcement/2021/suse-su-20211814-1/Advisory
www.suse.com/support/update/announcement/2021/suse-su-20211815-1/Advisory
www.suse.com/support/update/announcement/2021/suse-su-20211839-1/Advisory
access.redhat.com/errata/RHBA-2021:2955Advisory
access.redhat.com/documentation/…ARTICLE
security.access.redhat.com/data/csaf/v2/advisories/2021/rhba-2021_2955.jsonAdvisory
access.redhat.com/security/cve/CVE-2021-23017REPORT
bugzilla.redhat.com/show_bug.cgi?id=1963121REPORT
www.cve.org/CVERecord?id=CVE-2021-23017AdvisoryREPORT
nvd.nist.gov/vuln/detail/CVE-2021-23017AdvisoryOval
access.redhat.com/errata/RHSA-2021:2258Advisory
access.redhat.com/security/updates/classification/ARTICLE
security.access.redhat.com/data/csaf/v2/advisories/2021/rhsa-2021_2258.jsonAdvisory
access.redhat.com/errata/RHSA-2021:2259Advisory
security.access.redhat.com/data/csaf/v2/advisories/2021/rhsa-2021_2259.jsonAdvisory
access.redhat.com/errata/RHSA-2021:2278Advisory
security.access.redhat.com/data/csaf/v2/advisories/2021/rhsa-2021_2278.jsonAdvisory
access.redhat.com/errata/RHSA-2021:2290Advisory
security.access.redhat.com/data/csaf/v2/advisories/2021/rhsa-2021_2290.jsonAdvisory
access.redhat.com/errata/RHSA-2022:0323Advisory
security.access.redhat.com/data/csaf/v2/advisories/2022/rhsa-2022_0323.jsonAdvisory
ubuntu.com/security/CVE-2021-23017REPORT
www.x41-dsec.de/lab/advisories/x41-2021-002-nginx-resolver-copy/REPORT
ubuntu.com/security/notices/USN-4967-1Advisory
ubuntu.com/security/notices/USN-4967-2Advisory
security-tracker.debian.org/tracker/CVE-2021-23017Advisory
lists.opensuse.org/archives/…Advisory
lists.opensuse.org/archives/…Advisory

Vulnerability summary

Advisory lineage

Timeline

Description

CVSS metrics

EPSS trend

Known exploited

Public exploits

Weaknesses

Affected systems

References

Related vulnerabilities