apcupsd through 3.14.14 discloses uninitialized stack memory in getupsvar() in src/cgi/upsfetch.c (used by upsstats.cgi, multimon.cgi, and… (CVE-2026-103436)
Description
A vulnerability in apcupsd through version 3.14.14 causes uninitialized stack memory disclosure in the getupsvar() function within src/cgi/upsfetch.c. This affects CGI scripts such as upsstats.cgi, multimon.cgi, and upsfstats.cgi. When a STATUS line has fewer than three whitespace-separated tokens, sscanf does not assign a value to the destination buffer, but the function returns success, leading to uninitialized memory being printed in the HTTP response. The CVSS score is 3.7, indicating a medium severity issue.
CVSS v3.1
Score 3.7low
Affected software
pkg:deb/ubuntu/apcupsd?arch=source&distro=xenialpkg:deb/ubuntu/apcupsd?arch=source&distro=bionicpkg:deb/ubuntu/apcupsd?arch=source&distro=focalpkg:deb/ubuntu/apcupsd?arch=source&distro=jammypkg:deb/ubuntu/apcupsd?arch=source&distro=noblepkg:deb/ubuntu/apcupsd?arch=source&distro=stonkingpkg:deb/ubuntu/apcupsd?arch=source&distro=resoluteRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The apcupsd software versions up to and including 3.14.14 contain a vulnerability in the getupsvar() function located in src/cgi/upsfetch.c. This function is used by CGI scripts like upsstats.cgi, multimon.cgi, and upsfstats.cgi. The flaw occurs when the matched STATUS line has fewer than three whitespace-separated tokens; the sscanf call with format "%*s %*s %s" performs no assignment to the 'answer' buffer but returns success. Consequently, the caller prints the uninitialized stack memory content of 'answer' in the HTTP response, potentially disclosing sensitive information.
Potential Impact
The vulnerability results in the disclosure of uninitialized stack memory through HTTP responses generated by affected CGI scripts. This could leak sensitive information present in stack memory at the time of the request. The CVSS score of 3.7 reflects a low impact on confidentiality with no impact on integrity or availability. There is no indication of known exploits in the wild.
Mitigation Recommendations
No vendor advisory or patch information is provided in the data. Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, users should consider restricting access to the affected CGI scripts or disable them if not needed to reduce exposure.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2026-103436
- Osv Schema Version
- 1.7.0
- Ecosystems
- ["Ubuntu:16.04:LTS","Ubuntu:18.04:LTS","Ubuntu:20.04:LTS","Ubuntu:22.04:LTS","Ubuntu:24.04:LTS","Ubuntu:26.10","Ubuntu:26.04:LTS"]
- Cvss Version
- 3.1
Threat ID: 6ad3f4f62cdf04f656657601
Added to database: 10/17/2026, 22:21:42 UTC
Last enriched: 10/17/2026, 22:43:07 UTC
Last updated: 10/17/2026, 22:43:07 UTC
Views: 2
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