CVE-2026-39821
CVE.org · Published
- Record status
- Published
- Identifier year (not publication year)
- 2026
- Source publication
- Source updated
- Imported by cveboard
- Source snapshot
- cve_2026-10-24_midnight_baseline ·
CNA source text (English)
Invoking failure to reject ASCII-only Punycode-encoded labels in golang.org/x/net/idna
The ToASCII and ToUnicode functions incorrectly accept Punycode-encoded labels that decode to an ASCII-only label. For example, ToUnicode("xn--example-.com") incorrectly returns the name "example.com" rather than an error. This behavior can lead to privilege escalation in programs using the idna package. For example, a program which performs privilege checks on the ASCII hostname may reject "example.com" but permit "xn--example-.com". If that program subsequently converts the ASCII hostname to Unicode, it will inadvertently permits access to the Unicode name "example.com".
Scoped product and version facts
Fix information unknown; no fixed version is derived here. Missing information does not prove that no fix exists.
Exploitation unknown; this catalogue does not assess exploitation.
net/http
- Vendor
- Go standard library
- Product
- net/http
- Platforms
- Unknown
- Default status
unaffected- Package
- net/http
- Package collection
- https://pkg.go.dev
| Version (version) | Status (status) | Version scheme (versionType) | Exclusive end (lessThan) | Inclusive end (lessThanOrEqual) | Status changes (at → status) |
|---|---|---|---|---|---|
| 0 | affected | semver | 1.25.13 | Unavailable | None listed |
| 1.26.0-0 | affected | semver | 1.26.6 | Unavailable | None listed |
| 1.27.0-0 | affected | semver | 1.27.0-rc.3 | Unavailable | None listed |
net/http/internal/http2
- Vendor
- Go standard library
- Product
- net/http/internal/http2
- Platforms
- Unknown
- Default status
unaffected- Package
- net/http/internal/http2
- Package collection
- https://pkg.go.dev
| Version (version) | Status (status) | Version scheme (versionType) | Exclusive end (lessThan) | Inclusive end (lessThanOrEqual) | Status changes (at → status) |
|---|---|---|---|---|---|
| 0 | affected | semver | 1.25.13 | Unavailable | None listed |
| 1.26.0-0 | affected | semver | 1.26.6 | Unavailable | None listed |
| 1.27.0-0 | affected | semver | 1.27.0-rc.3 | Unavailable | None listed |
golang.org/x/net/idna
- Vendor
- golang.org/x/net
- Product
- golang.org/x/net/idna
- Platforms
- Unknown
- Default status
unaffected- Package
- golang.org/x/net/idna
- Package collection
- https://pkg.go.dev
| Version (version) | Status (status) | Version scheme (versionType) | Exclusive end (lessThan) | Inclusive end (lessThanOrEqual) | Status changes (at → status) |
|---|---|---|---|---|---|
| 0 | affected | semver | 0.55.0 | Unavailable | None listed |