Usermin through 2.570 Path Traversal File Write via detachall.cgi
Usermin through 2.570 with the mailbox module (Read Mail) is affected. The checked facts list no fixed version.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- Proof of concept public, per CISA
- Fix
- Fix or patch referenced
- Who is exposed
- Specific setups only
Do first: Check whether your setup matches what the bug needs. Usermin through 2.570 with the mailbox module (Read Mail) that contains detachall.cgi A victim must open Read Mail and use the download-all-attachments function
- Last modified
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 37/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: poc
- Automatable: no
- Technical impact: total
Summary
Usermin through 2.570 contains a path traversal vulnerability in mailbox/detachall.cgi that allows remote unauthenticated attackers to write files outside the temporary directory via unsanitized attachment filenames. Attackers can email attachments with ../ sequences in filenames, and when the recipient downloads all attachments, files like ~/.forward are overwritten, enabling command execution.
cve.now Index
- Exploitation15/40CISA rates a proof of concept as public
- Exposure12/25Specific setups only, reachable over the network without a login
- Reach?/20Unknown. No tracked technology or package matched
- Severity9.6/10CVSS 8.6, total technical impact per CISA
- No patch0/5No signal
What would change the score
- Would score about 72 if added to CISA KEV
- Would score about 67 if CISA's SSVC rates exploitation active
What to do
Check whether your setup matches what the bug needs.
Usermin through 2.570 with the mailbox module (Read Mail) that contains detachall.cgi A victim must open Read Mail and use the download-all-attachments functionApply the patch listed under Evidence.
Timeline
- CVE published
- First seen by cve.now
- CISA SSVC assessment
Exploitation: poc · Automatable: no · Technical impact: total
- Record last updated
Affected versions
- webmin usermin
through 2.570
Evidence 6
- Patch
- Report
- Repository
- Repository
- Link
- Link
Corrections
None so far.
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Questions about CVE-2026-123621
Is CVE-2026-123621 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. CISA's SSVC assessment notes a proof of concept exists. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
A path traversal flaw in mailbox/detachall.cgi lets a file be written to an arbitrary location as the victim user, with attacker-chosen contents. This can lead to command execution, for example by overwriting ~/.forward. The write happens when a victim opens Read Mail and uses the download-all-attachments function.Source: vulncheck.com, hackmd.io
Which versions are affected by CVE-2026-123621?
usermin: through 2.570.Source: cve.now feed data
Am I affected, and how do I check?
Usermin through version 2.570 that includes the mailbox module (Read Mail) and its detachall.cgi script. To check a setup, look at the installed Usermin version and confirm whether Read Mail is available in the Usermin interface.Source: vulncheck.com, hackmd.io
How do I fix CVE-2026-123621?
The checked facts do not list a fixed version or a workaround, so no upgrade target can be named from them. Check the vendor's advisory for a fix before relying on any version.Source: vulncheck.com, hackmd.io