No exploitation reportedFix available

CVE-2021-22945

Q: Is CVE-2021-22945 actively exploited?

Active exploitation of CVE-2021-22945 has not been confirmed. Its EPSS score was 6.7% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2021-22945?

CVE-2021-22945 has a CVSS v3 base score of 9.1 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H.

No exploitation reported by the sources we read.

Published2021-09-23
Fixed in9.0.6 · 8.2.12
WeaknessCWE-415

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

When sending data to an MQTT server, libcurl <= 7.73.0 and 7.78.0 could in some circumstances erroneously keep a pointer to an already freed memory area and both use that again in a subsequent call to send data and also free it *again*.

Timeline

dates in UTC

2021-09-2313:15CVE publishedNVD

Versions per branch

NVD

Splunk universal forwarder

Branch	Affected	Fixed in	Source
9.0	≥ 9.0.0, < 9.0.6	9.0.6	NVD
8.2	≥ 8.2.0, < 8.2.12	8.2.12	NVD
9.1	= 9.1.0	no fix published	NVD

Fedoraproject fedora

Branch	Affected	Fixed in	Source
33.x	= 33	no fix published	NVD
35.x	= 35	no fix published	NVD

Oracle mysql server

Branch	Affected	Fixed in	Source
5.7	≥ 5.7.0, ≤ 5.7.35	no fix published	NVD
8.0	≥ 8.0.0, ≤ 8.0.26	no fix published	NVD

14 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As hackerone, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

https://github.com/curl/curl
Affected
- = curl 7.73.0 to and including 7.78.0no fix stated

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of Use CVE recordupdated 2022-12-19

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

curlUbuntu:22.04:LTSall versions · fixed in 7.74.0-1.3ubuntu2
curlUbuntu:20.04:LTSall versions · fixed in 7.68.0-1ubuntu2.7
curlUbuntu:18.04:LTSall versions · fixed in 7.58.0-2ubuntu3.15
curlopenSUSE:Tumbleweedall versions · fixed in 7.79.1-1.1
curlopenEuler:20.03-LTS-SP2all versions · fixed in 7.71.1-11.oe1
curlopenEuler:20.03-LTS-SP1all versions · fixed in 7.71.1-11.oe1
curlMageia:8all versions · fixed in 7.74.0-1.4.mga8
curlDebian:14all versions · fixed in 7.79.1-1

19 more package ranges on OSV.dev

Vendor advisories

CVE-2021-22945 Red Hat Product Security5 known affected
curl: use-after-free and double-free in MQTT sending
rh-dotnet21-curl.src as a component of .NET Core 2.1 on Red Hat Enterprise Linux · rh-dotnet21-libcurl as a component of .NET Core 2.1 on Red Hat Enterprise Linux · rh-dotnet21-libcurl-devel as a component of .NET Core 2.1 on Red Hat Enterprise Linux · +2 more
ICSA-23-348-10 CISA5 known affected
Siemens SIMATIC S7-1500
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) · SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) · +2 more
SSA-398330 Siemens ProductCERT5 known affected
SSA-398330: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP >= V3.1.0 and < V3.1.5
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= V3.1.0 < V3.1.5 · SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= V3.1.0 < V3.1.5 · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= V3.1.0 < V3.1.5 · +2 more
ICSA-22-069-09 CISA1 known affected
Siemens SINEC INS
SINEC INS
SSA-389290 Siemens ProductCERT1 known affected
SSA-389290: Third-Party Component Vulnerabilities in SINEC INS
SINEC INS

Full record on NVD

Fix

Update Splunk universal forwarder to 9.0.6 · 8.2.12
Vendor fix CISA ICSA-23-348-10 · 5 productsUpdate to V3.1.5 or later version
Vendor fix Siemens ProductCERT SSA-398330 · 1 productUpdate to V3.1.5 or later version
Vendor fix Siemens ProductCERT SSA-389290 · 1 productUpdate to V1.0.1.1 or later version
Vendor fix CISA ICSA-22-069-09 · 1 productUpdate to V1.0.1.1 or later version
Mitigation from the vendor CISA ICSA-23-348-10 · 5 productsOnly build and run applications from trusted sources.
No fix planned, says the vendor Red Hat Product Security CVE-2021-22945 · 5 productsOut of support scope

Advisories and patches

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof of concept: PoC-in-GitHubno public repository identifiedread 2026-11-08
Metasploit modules: none listed

Sources

CISA-ADPSSVC decisionnone2024-03-28
CISA-ADPCVSS 3.19.12025-06-09
NVDCVSS 3.19.1read 2026-10-23
NVDCVSS 2.05.8read 2026-10-23
CISA-ADPweakness (CWE)CWE-4152025-06-09
CNAweakness (CWE)CWE-415known since 2026-10-23
NVDweakness (CWE)CWE-415read 2026-10-23
FIRST EPSSEPSS score6.7 %2026-11-08
OSVaffected packages—
GitHub Advisoriesadvisory—

Identifiers

AZL-6368same flawAzure Linux · MIT
EUVD-2021-10073same flawENISA EUVD · LicenseRef-ENISA-legal-notice
GHSA-22mx-9r92-42g8same flawGitHub Advisory Database · CC-BY-4.0
JLSEC-2025-29same flawJulia Security Advisories · CC-BY-4.0
DSA-5197-1advisory covering several CVEsDebian · LicenseRef-unstated
MGASA-2021-0438advisory covering several CVEsMageia · LicenseRef-unstated
OESA-2021-1382advisory covering several CVEsopenEuler · LicenseRef-unstated
openSUSE-SU-2024:10582-1advisory covering several CVEsopenSUSE · LicenseRef-unstated
USN-5079-1advisory covering several CVEsUbuntu

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Published: 2021-09-23
Last Modified: 2026-10-14
NVD status: Modified
GitHub Advisory: GHSA-22mx-9r92-42g8

Frequently asked questions

What is CVE-2021-22945?

Is CVE-2021-22945 actively exploited?

Active exploitation of CVE-2021-22945 has not been confirmed. Its EPSS score was 6.7% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-22945?

CVE-2021-22945 has a CVSS v3 base score of 9.1 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H.

Running curl? Hear about its next vulnerability

Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».

Get alerts for this product CISA KEV additions, November 2026 Search CVEs

No credit card required · No monthly cap on website lookups · 250 API requests/month

Go further

Following what attackers exploit right now? The CISA KEV additions of the month, with their patch deadlines.
Running this software? Vulnerability monitoring alerts you to new vulnerabilities in your products.

Related vulnerabilities

Same product first, then the same vendor advisory and the same publication week.

Back to CVE Database

Sources for this record

MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE®). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy.

CVE records are reproduced under the CVE Program Terms of Use: MITRE grants a perpetual, royalty-free licence to reproduce and redistribute them, provided this designation and the licence travel with every copy. Read the licence

This product uses data from the NVD API but is not endorsed or certified by the NVD.

Sources and licences of the CVE data