Security readout for executives and security teams
Plain-English summary
CVE-2021-40648 describes a memory corruption issue in man2html 1.6g triggered by a crafted filename. The public bundle does not provide a CVSS score, vendor advisory, patch status, or confirmed exploitation evidence, so urgency depends on whether this tool processes untrusted filenames in your environment.
Executive priority
Prioritize discovery first. This is potentially serious memory corruption, but business urgency cannot be rated reliably without confirming deployment and exposure to untrusted input.
Technical view
The CVE states a crafted filename can overwrite heap chunk metadata, including the next chunk size and linked-list fields. When the next chunk is later freed, man2html may free an attacker-controlled amount of memory. The source does not define impact beyond memory corruption.
Likely exposure
Exposure is most plausible where man2html 1.6g is installed and reachable through CGI, documentation conversion, or other workflows that accept untrusted filenames. The provided affected-product metadata is incomplete and lists n/a values.
Exploitation context
The bundle includes a third-party gist reference, but no KEV listing and no cited source confirming active exploitation. Treat exploit maturity as unconfirmed from the provided evidence.
Researcher notes
The CVE record is sparse: no CVSS, CWE, concrete affected CPEs, vendor fix, or confirmed exploitation. Analysis should stay scoped to man2html 1.6g and the heap metadata corruption described in the record.
Mitigation direction
- Inventory systems for man2html 1.6g or distribution packages containing it.
- Check vendor, maintainer, or OS distribution advisories for fixed builds or removal guidance.
- Remove or disable man2html where it is not operationally required.
- Prevent untrusted users from supplying filenames to man2html workflows.
- Isolate any exposed CGI or conversion service until vendor guidance is confirmed.
Validation and detection
- Confirm whether man2html 1.6g is installed on servers, images, and legacy web hosts.
- Identify any web, CGI, or automation path invoking man2html with user-controlled filenames.
- Review package advisories from the relevant OS distribution or maintainer.
- Check logs for unexpected man2html invocation patterns or untrusted conversion requests.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CVE-2021-40648 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://gist.github.com/untaman/cb58123fe89fc65e3984165db5d40933CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.