CVE-2026-5772: MatchDomainName 1-Byte Stack Buffer Over-Read in Hostname Validation
Vulnerability summary
CVE-2026-5772 is a medium (CVSS 5.3) Buffer Over-read vulnerability in wolfssl. EPSS estimates a 0.23% chance of exploitation in the next 30 days, higher than 13.5% of scored vulnerabilities.
Not severe (CVSS 2.1, network access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Timeline
- 09-04-2026PublishedVulnerability first disclosed.
- 10-04-2026Last modifiedVulnerability information updated.
Description
A 1-byte stack buffer over-read was identified in the MatchDomainName function (src/internal.c) during wildcard hostname validation when the LEFT_MOST_WILDCARD_ONLY flag is active. If a wildcard * exhausts the entire hostname string, the function reads one byte past the buffer without a bounds check, which could cause a crash.
CVSS metrics
7 scores · 5 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated2.1LowCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
- NVDNIST2.1LowCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/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
- OSV · UbuntuEcosystem advisory · calculated5.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- OSV · DebianEcosystem advisory · calculated5.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- OSV · AlpineEcosystem advisory · calculated5.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
EPSS trend
Probability
0.23%
Chance of exploitation in the next 30 days
Percentile
14%
Versus all other CVEs
30-day change
Decrease -0.12 pp
From 0.35% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, low-privilege account, user interaction (CVSS vector). Other conditions: not stated in public data.
Alpine1 product
- wolfssl< 5.9.1-r0
Debian1 product
- wolfsslAll versions (No fix recorded)
Ubuntu1 product
- wolfsslAll versions (No fix recorded)
Wolfssl1 product
- wolfssl≤ 5.9.0 | < 5.9.1
4 vendors · 4 products
