CVE Explorer
CVE-2026-44042
UltraVNC repeater through 1.8.2.2 contains an off-by-one error in the Base64 decode helper used for HTTP Basic authentication. In repeater/webgui/webutils.c:817, the wi_uudecode() function checks whether the input length exceeds the output buffer with a strict greater-than comparison (>), while the correct check should be greater-than-or-equal (>=). When strlen(authdata) equals sizeof(decode), the decoded output length (approximately 3/4 of input) does not overflow the buffer in current practice
Known exploited
Not asserted
Disputed
No
Stale source
No
Conflicts
0
Affected products and versions
1 source assertion{"defaultStatus":"unaffected","modules":["repeater"],"product":"UltraVNC","vendor":"uvnc","versions":[{"lessThanOrEqual":"1.8.2.2","status":"affected","version":"0","versionType":"custom"}]}
- cve_program_cvelist_v5affectedurn:baitaphish:normalized-source-record:v2:962a781af5844258afd3837bc9799356cf89cef41173ac61df7f408fcdaf976b · sha256:734c2dd9d9511025… · /containers/cna/affected/0
Provider-owned CVSS observations
1 source assertion{"metric":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"LOW","baseScore":3.7,"baseSeverity":"LOW","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L","version":"3.1"},"metric_type":"cvssV3_1"}
- cve_program_cvelist_v5cvssurn:baitaphish:normalized-source-record:v2:962a781af5844258afd3837bc9799356cf89cef41173ac61df7f408fcdaf976b · sha256:734c2dd9d9511025… · /containers/cna/metrics/0/cvssV3_1
CWE assertions
1 source assertion{"cweId":"CWE-193","description":"Off-by-one Error","lang":"en","type":"CWE"}
- cve_program_cvelist_v5cweurn:baitaphish:normalized-source-record:v2:962a781af5844258afd3837bc9799356cf89cef41173ac61df7f408fcdaf976b · sha256:734c2dd9d9511025… · /containers/cna/problemTypes/0/descriptions/0
Source references
3 source assertions{"name":"UltraVNC source repository","tags":["product"],"url":"https://github.com/ultravnc/UltraVNC"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:962a781af5844258afd3837bc9799356cf89cef41173ac61df7f408fcdaf976b · sha256:734c2dd9d9511025… · /containers/cna/references/1
{"name":"UltraVNC project page","tags":["vendor-advisory"],"url":"https://uvnc.com/"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:962a781af5844258afd3837bc9799356cf89cef41173ac61df7f408fcdaf976b · sha256:734c2dd9d9511025… · /containers/cna/references/0
{"url":"https://www.securin.io/zero-days/cve-2026-44042-wi-uudecode-off-by-one-bounded-ultravnc-repeater"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:962a781af5844258afd3837bc9799356cf89cef41173ac61df7f408fcdaf976b · sha256:734c2dd9d9511025… · /containers/cna/references/2
Attribution and limitations
- CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →
Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.