CVE-2026-46644 symfony/polyfill-intl-idn accepts xn-- labels whose Punycode payload decodes to ASCII-only: insecure equivalence

Symfony Polyfill backports PHP features and provides compatibility layers for extensions and functions. From 1.17.1 until 1.38.1, symfony/polyfill-intl-idn accepts xn-- labels whose Punycode payload is empty or decodes to ASCII-only code points because Idn::process does not enforce the UTS 46...

golang.org/x/net/idna: golang: net/http: golang.org/x/net/idna: Privilege escalation via incorrect Punycode label processing

A flaw was found in golang.org/x/net/idna. ToASCII and ToUnicode incorrectly accept Punycode-encoded labels that decode to an ASCII-only hostname for example, xn--example-.com returns example.com instead of an error. Applications that validate the ASCII form then convert to Unicode may grant acce...

CVE-2026-46644: symfony/polyfill-intl-idn accepts xn-- labels whose Punycode payload decodes to ASCII-only: insecure equivalence

More info at https://symfony.com/cve-2026-46644...

CVE-2026-39821

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...

CVE-2026-39821

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...

CVE-2026-39821

CVE-2026-39821 affects golang.org/x/net/idna; ToASCII/ToUnicode incorrectly accept Punycode-encoded labels that decode to ASCII-only labels (e.g., xn--example-.com). The issue can enable privilege escalation in programs that validate ASCII hostnames but later convert to Unicode, potentially grant...

idna: idna accepts Punycode labels that do not produce any non-ASCII when decoded

A flaw was found in idna crate. This vulnerability allows hostname spoofing and potential privilege escalation via specially crafted Punycode labels that render as ASCII or empty labels, leading to incorrect equality comparisons during hostname validation...

HackerOne: LLM03: Training Data Poisoning via ASCII decoding

Vulnerability description not provided...

PT-2026-42782

Name of the Vulnerable Software and Affected Versions idna affected versions not specified Description The ToASCII and ToUnicode functions incorrectly accept Punycode-encoded labels that decode to an ASCII-only label. For instance, ToUnicode"xn--example-.com" returns "example.com" instead of an...