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Public proof of conceptFix available

CVE-2021-22926

A public proof of concept exists; no exploitation attested.

  • Published2021-08-05
  • WeaknessCWE-295 · CWE-840

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

libcurl-using applications can ask for a specific client certificate to be used in a transfer. This is done with the `CURLOPT_SSLCERT` option (`--cert` with the command line tool).When libcurl is built to use the macOS native TLS library Secure Transport, an application can ask for the client certificate by name or with a file name - using the same option. If the name exists as a file, it will be used instead of by name.If the appliction runs with a current working directory that is writable by other users (like `/tmp`), a malicious user can create a file name with the same name as the app wants to use by name, and thereby trick the application to use the file based cert instead of the one referred to by name making libcurl send the wrong client certificate in the TLS connection handshake.

Timeline

dates in UTC
  1. 2021-08-0521:15CVE publishedNVD

Versions per branch

NVD
Oracle peoplesoft enterprise peopletools
BranchAffectedFixed in
8.57= 8.57no fix published
8.58= 8.58no fix published
8.59= 8.59no fix published
Splunk universal forwarder
BranchAffectedFixed in
9.0≥ 9.0.0, < 9.0.69.0.6
8.2≥ 8.2.0, < 8.2.128.2.12
9.1= 9.1.0no fix published
Oracle mysql server
BranchAffectedFixed in
5.7≥ 5.7.0, ≤ 5.7.35no fix published
8.0≥ 8.0.0, ≤ 8.0.26no fix published

16 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
    • = curll 7.33.0 to and include 7.77.0no fix stated

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE 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

  • curlopenEuler:20.03-LTS-SP2all versions · fixed in 7.71.1-10.oe1
  • curlopenEuler:20.03-LTS-SP1all versions · fixed in 7.71.1-10.oe1
  • curlAzure Linux:2all versions · fixed in 7.82.0-1
  • curlAlpine:v3.11from 7.33.0 · fixed in 7.67.0-r5
  • curl-7.69.1Echoall versions · fixed in 7.69.1+e1

Vendor advisories

  • CVE-2021-22926 Red Hat Product Security2 known affected

    curl: CURLOPT_SSLCERT mixup with Secure Transport

    curl.src as a component of Red Hat Ceph Storage 2 · libcurl as a component of Red Hat Ceph Storage 2

  • 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

  1. Vendor fix CISA ICSA-23-348-10 · 5 productsUpdate to V3.1.5 or later version
  2. Vendor fix Siemens ProductCERT SSA-398330 · 1 productUpdate to V3.1.5 or later version
  3. Vendor fix Siemens ProductCERT SSA-389290 · 1 productUpdate to V1.0.1.1 or later version
  4. Vendor fix CISA ICSA-22-069-09 · 1 productUpdate to V1.0.1.1 or later version
  5. Mitigation from the vendor CISA ICSA-23-348-10 · 5 productsOnly build and run applications from trusted sources.
  6. No fix planned, says the vendor Red Hat Product Security CVE-2021-22926 · 2 productsOut of support scope

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • CISA-ADPSSVC decisionpoc2026-05-28
  • CISA-ADPCVSS 3.17.52026-05-28
  • NVDCVSS 3.17.5read 2026-10-23
  • NVDCVSS 2.05read 2026-10-23
  • CNAweakness (CWE)CWE-840known since 2026-10-23
  • NVDweakness (CWE)CWE-295read 2026-10-23
  • FIRST EPSSEPSS score15.1 %read 2026-11-10
  • OSVaffected packages—
  • GitHub Advisoriesadvisory—

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2021-08-05
Last Modified
2026-10-14
NVD status
Modified
GitHub Advisory
GHSA-5xph-62q2-pxff

Frequently asked questions

What is CVE-2021-22926?

libcurl-using applications can ask for a specific client certificate to be used in a transfer. This is done with the `CURLOPT_SSLCERT` option (`--cert` with the command line tool).When libcurl is built to use the macOS native TLS library Secure Transport, an application can ask for the client certificate by name or with a file name - using the same option. If the name exists as a file, it will be used instead of by name.If the appliction runs with a current working directory that is writable by other users (like `/tmp`), a malicious user can create a file name with the same name as the app wants to use by name, and thereby trick the application to use the file based cert instead of the one referred to by name making libcurl send the wrong client certificate in the TLS connection handshake.

Is CVE-2021-22926 actively exploited?

A proof-of-concept exploit exists for CVE-2021-22926, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2021-22926?

CVE-2021-22926 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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