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CVE-2021-22945

32
FAUCET Score

CVE-2021-22945 is a critical double-free vulnerability affecting libcurl versions up to 7.73.0 and 7.78.0 when interacting with MQTT servers, potentially impacting products from Apple, Debian, Oracle, and others. This flaw allows an attacker to trigger a use-after-free and double-free condition, leading to denial of service or arbitrary code execution with a CVSS score of 9.1 (Critical). While the vulnerability is severe, there is currently no evidence of active exploitation, publicly available exploit code, or significant community discussion surrounding it.

Impacted Technologies

VendorProductVersion(s)CPE
>= 7.73.0, <= 7.78.0CPE matchmatch criteria
cpe:2.3:a:haxx:libcurl:*:*:*:*:*:*:*:*
33CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
35CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
Range not provided by sourceCPE matchmatch criteria
cpe:2.3:a:netapp:cloud_backup:-:*:*:*:*:*:*:*
Range not provided by sourceCPE matchmatch criteria
cpe:2.3:a:netapp:clustered_data_ontap:-:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

9.1CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.2
CvssVersion
3.1

Exploit Intelligence

EPSS Score
6.68%
Probability of exploitation in next 30 days
EPSS Percentile
93.2%
Percentile rank of EPSS score among Peer Group
As of 2026-07-24
Model: v2026.06.15
This CVE's current EPSS score of 0.0668 is in the 88th percentile among its peer group of 36,829 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (7)

hikvisionpatch availablevia llm_extracted
microsoftpatch availablevia msrc
Product: 18988-16820Fixed in: 7.76.0-6
microsoftpatch availablevia msrc
Product: cm1 curl 7.76.0-6 on CBL Mariner 1.0Fixed in: 7.76.0-6
microsoftpatch availablevia msrc
Product: cbl2 curl 7.82.0-1 on CBL Mariner 2.0Fixed in: 7.82.0-1
microsoftpatch availablevia msrc
Product: 18989-16823Fixed in: 7.82.0-1
oraclepatch availablevia nvd_reference
View patch
zimbrapatch availablevia llm_extracted
Fixed in: 8.2.12, 9.0.6, 9.1.1

Vendor Advisories (4)

zimbrallm-zimbra-9542faa91a6d6884HIGH

August Third Party Package Updates in Splunk Universal Forwarder

Aug 30, 2023
redhatCVE-2021-22945Moderate

curl: use-after-free and double-free in MQTT sending

Sep 15, 2021
hikvisionllm-hikvision-fe5361da34ba171aMEDIUM

UAF and double free in MQTT sending

Sep 15, 2021
microsoft2021-Sep/CVE-2021-22945Critical

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*.

Sep 14, 2021

References

cert-portal.siemens.com / productcert/pdf/ssa-389290.pdf
PatchThird Party Advisory
seclists.org / fulldisclosure/2022/Mar/29
Mailing ListThird Party Advisory
hackerone.com / reports/1269242
ExploitPatchThird Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/APOAK4X73EJTAPTSVT7IRVDMUWVXNWGD
Mailing ListThird Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/RWLEC6YVEM2HWUBX67SDGPSY4CQB72OE
Mailing ListThird Party Advisory
security.gentoo.org / glsa/202212-01
Third Party Advisory
security.netapp.com / advisory/ntap-20211029-0003
Third Party Advisory
support.apple.com / kb/HT213183
Third Party Advisory
debian.org / security/2022/dsa-5197
Third Party Advisory
oracle.com / security-alerts/cpuoct2021.html
PatchThird Party Advisory