CVE-2026-81738: openvpn Stack-based Buffer Overflow
CVSS: 2.3v4.0LowAwaiting analysis
AliasesUBUNTU-CVE-2026-81738
Published 07-09-2026Last modified 08-09-2026
Vulnerability summary
CVE-2026-81738 is a low (CVSS 2.3) Stack-based Buffer Overflow vulnerability in openvpn. EPSS estimates a 0.33% chance of exploitation in the next 30 days, higher than 24.9% of scored vulnerabilities.
CVSS score
2.3/10
010
Low · v4.0 (CVE.org)EPSS score
0.33%
0%100%
Low · 0.00 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Timeline
- 07-09-2026PublishedVulnerability first disclosed.
- 08-09-2026Last modifiedVulnerability information updated.
Description
OpenVPN 2.5.0 through 2.7.6 on Windows using the tap-windows6 driver allows attackers to trigger an out-of-bounds write via crafted DOMAIN-SEARCH entries
CVSS metrics
3 scores · 3 sources · 1 versionLow 2.3Preferred score · CVE.org (CNA)
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:N/VI:L/VA:L/SC:N/SI:L/SA:LSourcesAll 3 agree
- OSV · UbuntuEcosystem advisory · calculated2.3LowCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:N/VI:L/VA:L/SC:N/SI:L/SA:L
- NVDNIST2.3LowCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:N/VI:L/VA:L/SC:N/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS trend
Probability
0.33%
Chance of exploitation in the next 30 days
Percentile
25%
Versus all other CVEs
30-day change
0.00 pp
From 0.33% on 21-09-2026
21-09-202621-10-2026
EPSS score0.33%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-121Stack-based Buffer OverflowA stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).
- CWE-193Off-by-one ErrorA product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value.
- CWE-787Out-of-bounds WriteThe product writes data past the end, or before the beginning, of the intended buffer.
Affected systems
Openvpn1 product
- openvpn≥ 2.5.0, ≤ 2.7.6
Ubuntu1 product
- openvpnAll versions (No fix recorded)
2 vendors · 2 products